Regina Vierra received benefits under the Aid to Families with Dependent Children (AFDC) program. Because of circumstances beyond her control, she filed a required form one business day late. The State of Hawaii, which administers this cooperative federal-state program through its Department of Social Services, disqualified Vierra from one month’s benefits because of the one day delay. The district court granted summary judgment upholding the denial of benefits. Vierra appeals. We reverse and grant summary judgment for Vierra.
BACKGROUND
1. Facts
Appellant Regina Vierra never finished high school, and does not read well. She has one child. In August 1979, Vierra and her child started receiving AFDC benefits. Until September 1987, this was her sole source of income.
In September 1987, Vierra began part-time work under Hawaii’s Department of Social Services (the Department) Work Incentive (“WIN”) Program. She promptly reported the employment on a Change in Status Form and on her first Monthly Eligibility Report Form (“MERF”) filed after she began part-time work. Before starting her part-time job, Vierra had from time to time submitted late MERF forms without incident or penalty.
After Vierra notified the Department of her part-time work, the Department failed to instruct her on how to fill out a MERF form when part-time employment was involved. Even after learning of Vierra’s employment, her caseworker never instructed Vierra on how to verify what she had been paid, nor on the need to submit pay verification information. The only instructions Vierra ever received were the standard instructions contained on the MERF form itself:
If this form is late, is incomplete, or is not returned, your check, food stamps, and medical benefits may be delayed or stopped. In addition, no earned income deductions will be allowed in determining the amount of your welfare check.... Attach pay stubs and verification of changes.
Vierra received her first pay checks in October 1987. A friend told her that pays-tubs had to be attached to her MERF form if Vierra wanted to maintain her AFDC benefits. Vierra was not informed, either by her friend, her caseworker, or the MERF form instructions, that pay verification could be made by any means other than pay stubs.
Under the regulations, Vierra was first required to attach pay verification to her MERF form on November 6, 1987. To file what she considered to be a complete form, Vierra repeatedly requested pay stubs from her employer (the employer did not attach stubs to her paychecks). Her employer did not produce the stubs, even after eight requests. Afraid that she would not be able to meet her November 6 deadline, Vierra unsuccessfully attempted to contact her caseworker. The caseworker did not return Vierra’s call.
On November 9, a Monday, one business day after her MERF filing deadline, Vierra received paystubs from her employer and immediately filed them with her MERF form. The Department determined that Vi-erra should be denied the Earned Income Disregards (EIDs) necessary to bring her income within prescribed AFDC limits for that month because the filing was late, and because the Department believed informa*1375tion provided by the employer on the pays-tubs was incomplete and confusing. With the EIDs, Vierra would have received $198.00 in AFDC benefits. Without the EIDs, she received no AFDC benefits because her earned income amounted to $420.00 for the month of November, $12.00 over her standard need.
The Department informed Vierra, in an adverse action notice sent November 17, 1987, that excess countable income disqualified her for all AFDC benefits in December 1987. Vierra responded by immediately filing a fair hearing request. In a hearing held on January 21, 1988, the fair hearing officer affirmed the Department’s decision. Though the officer regretted the “egregious” actions of Vierra’s employer, she held that employer caused delay did not fall within the Hawaii Department of Social Services’ definition of the “good cause” exception to filing requirements.
Vierra took her case to a Hawaii state court. Before any action was taken on the appeal, Hawaii’s Department of Social Services filed a Third Party Complaint against the United States Department of Health and Human Services. The Secretary of Health and Human Services (the Secretary) removed the entire matter to the United States District Court.
The district court affirmed the Department’s action on the grounds that (1) Hawaii's restrictive definition of “good cause” to excuse late MERF filings did not defeat general AFDC purposes, and (2) the Secretary’s tacit approval of Hawaii’s narrow “good cause” definition was entitled to deference.
2. “WIN” Programs, EIDs, and the “Good Cause” System
“The AFDC program is a cooperative federal-state effort established by Congress to provide financial assistance and other services to needy dependent children and parents or relatives with whom they live.” Figueroa v. Sunn, 884 F.2d 1290, 1291 (9th Cir.1989). One specific purpose of the program is to encourage adult members of families receiving AFDC benefits “to attain or retain capability for the maximum self-support and personal independence consistent with the maintenance of continuing parental care and protection.” Id. (quoting 42 U.S.C.A. § 601 (1983)). In recognition of the fact that the AFDC system can create a financial incentive not to work, Congress enacted Earned Income Disregard (EID) provisions. Drysdale v. Spirito, 689 F.2d 252, 254 (1st Cir.1982). “By ‘disregarding’ certain classes of income that would otherwise be counted in the [AFDC] eligibility and benefits determinations, more families are deemed eligible for assistance than would otherwise be the case, and their benefits are increased.” Simpson v. Hegstrom, 873 F.2d 1294, 1295 (9th Cir.1989).
Earned Income Disregards are central to the effective operation of work incentive or “WIN” programs run by states pursuant to 42 U.S.C.A. § 645(b)(1)(B) (1983). Without these disregards, “increased income reduces the size of the AFDC grant, [and] members of AFDC families may have little financial incentive to work.” Drysdale v. Spirito, 689 F.2d at 254. The Secretary of Health and Human Services has promulgated regulations requiring state agencies to follow particular guidelines in defining earned income for purposes of the disregard. See Figueroa v. Sunn, 884 F.2d at 1291 (giving examples of earned income excluded by the disregards).
In 1980, Congress enacted legislation requiring timely eligibility reports as a means for ensuring correct eligibility determinations and benefit levels. 42 U.S.C.A. § 602(a)(8)(B)(i)(III) (West Supp.1989). It did so in response to concerns that “a large percentage of the payment errors made in the AFDC program relate to earned income and the failure of the recipient to report the correct amount of any changes in amount earned.” S.Rep. No. 336, 96th Cong., 2d Sess., reprinted in 1980 U.S. Code Cong. & Admin.News 1448, 1538. Earned income disregards are required to *1376be withheld from tardy filers except those who show good cause.1
The Secretary has promulgated a regulation allowing the State to specify the nature of “good cause” in the context of late filing. 45 C.F.R. § 233.20(a)(ll)(iii)(C) (1988). Pursuant to this regulation, Hawaii’s Department of Social Services promulgated a restrictive definition of good cause which recognizes only two exceptions from late filing penalties: “Good cause exists when there 'is verification [that] ... [a]n illness prevented the recipient from ... submitting a completed Monthly Eligibility Report on a timely basis; or ... [t]he recipient has experienced a problem in mailing which the recipient could not prevent.” H.A.R. § 17-621-40(d)(3).
DISCUSSION
This court reviews a grant of summary judgment de novo, affirming the district court’s grant only where no genuine issue of material fact exists and the moving party is entitled to prevail as a matter of law. Figueroa v. Sunn, 884 F.2d at 1292. The facts, including the fact that Vierra’s MERF form was filed late because of circumstances beyond her control, are undisputed by the parties. We must therefore determine whether the state defendant and the third party federal defendant are entitled to prevail as a matter of law.
A court may invalidate an agency regulation if it “is not reasonably related to the purposes of the statute it seeks to implement,” id. at 1293, or if legislative history reveals a clear expression of congressional intent that runs contrary to the regulation. Connecticut Dept. of Income Maintenance v. Heckler, 471 U.S. 524, 538, 105 S.Ct. 2210, 2217, 85 L.Ed.2d 577 (1985).2 This is so despite the deference generally afforded “an agency’s construction of the statute it is charged with implementing, and ... the procedures it adopts for implementing that statute.” Simpson v. Hegstrom, 873 F.2d at 1297 (quoting Heckler v. Chaney, 470 U.S. 821, 832, 105 S.Ct. 1649, 1656, 84 L.Ed.2d 714 (1985)).
To decide what deference is due to the Hawaii Department of Social Services’ good cause regulation, we review three distinct agency determinations. First, there is the question whether the Secretary misinterpreted Congressional intent when he promulgated the regulation authorizing states to define “good cause” for purposes of late MERF form filings. Second, there is the question whether the Secretary acted unreasonably when he tacitly approved Hawaii’s good cause definition. Third, there is the question whether the state agency, the Hawaii Department of Social Services, misinterpreted federal legislation and agen*1377cy regulations in promulgating the state’s regulation.
To decide what deference is due the good cause definition at issue in this case, we separately discuss each agency determination listed above.
1. Federal Regulation Delegating Good Cause Definitions to the States
It is not clear from the statutory language that Congress intended to leave the definition of good cause for late MERF form filings to the states. Indeed, the plain language of the section indicates that Congress meant to leave to the states the determination of “timely report,” but not of “good cause.”
The statute relied upon by the Secretary for delegating the definition of good cause to the states reads as follows: “the State Agency ... shall not disregard ... any earned income of [designated persons who] failed without good cause to make a timely report (as prescribed by the State plan pursuant to paragraph (14)).” 42 U.S.C. § 602(a)(8)(B)(i)(III) (emphasis added). As pointed out by the appellant, the parenthetical phrase “as prescribed by the State plan” modifies “timely report,” not “good cause.”
The regulation promulgated by the Secretary to implement this section, 45 C.F.R. § 233.20(a)(ll)(iii)(C) (1989), does not track the language in the statute drafted by Congress. Indeed, the Secretary’s regulation reverses the responsibility described in the statute for determining “good cause” (which the regulation assigns to the States) and of “timely reports” (which the regulation defines by another federal regulation). The Secretary’s regulation reads: “[t]he applicable earned income disregards ... of this paragraph do not apply to [an individual’s earned income] ... in which ... [a]n individual failed without good cause (as specified in the State plan) to make a timely report (as defined in § 233.37(c)).”
“[Q]ualifying phrases are generally applied to the immediately preceding phrase and not to phrases more remote.” First Charter Fin. Corp. v. United States, 669 F.2d 1342, 1350 (9th Cir.1982). A reading of the section which logically associates “as prescribed by the State plan” to the timeliness of the report and not to good cause is a natural reading which relies on the grammatical structure of the statute. A reading of a statute which relies on grammatical structure is an approach often used by the courts. See e.g., United States v. Ron Pair Enter., 489 U.S. 235, 109 S.Ct. 1026, 1030, 103 L.Ed.2d 290 (1989) (“This reading is also mandated by the grammatical structure of the statute.”); Tello v. McMahon, 677 F.Supp. 1436, 1443 (E.D.Cal., 1988) (ruling that “Congress left the determination of timeliness [in section 602(a)(8)(B)(i)(III) ] to the states” based on the position of parenthetical clarification).
As further support for this argument, paragraph (14) referred to in the parenthetical deals specifically with timeliness issues, not good cause questions. See 42 U.S.C.A. § 602(a)(14) (West Supp.1990).3
We do not, therefore, believe that the plain language of the statute required the Secretary to delegate responsibility for defining “good cause” for untimely MERF form filings to the states. The next question is whether Congress permitted the Secretary to delegate the responsibility for defining good cause to the states even though the statute does not require such delegation.
“In the absence of a statutory definition [of a term] ... it is appropriate to consider the Secretary’s interpretation of that term.” Connecticut Dept. of Income Maintenance v. Heckler, 471 U.S. at 530, 105 S.Ct. at 2214 (footnote omitted). In this case, however, the Secretary did not define “good cause" for the purpose of late *1378MERF form filings, but instead delegated that decision to the states. Such a delegation is not impermissible per se. In the context of other AFDC disputes, we have held that “[a] conspicuous lack of guidance by Congress ... confirms breadth of discretion granted to states.” Largo v. Sunn, 835 F.2d 205, 208 (9th Cir.1987).
Nevertheless, when the Secretary delegates to a state’s discretion the definition of an important statutory term, the states’ authority to define the term can not exceed the authority given the Secretary by Congress in the first place. Congress has expressly described the Secretary’s authority in the context of the AFDC program. The Secretary is authorized to “make and publish such rules and regulations, not inconsistent with [the AFDC program], as may be necessary to the efficient administration of the functions with which [he] is charged under [the AFDC program].” 42 U.S.C.A. § 1302(a) (West Supp. 1990). The Secretary may thus delegate definitional responsibilities to the states only to the extent that the state’s determinations are also consistent with the AFDC program generally. See United States v. Larionoff, 431 U.S. 864, 873, 97 S.Ct. 2150, 2156, 53 L.Ed.2d 48 (1977) (“regulations, in order to be valid must be consistent with the statute under which they are promulgated”) (footnote omitted). In this case, appellant argues, and we agree, that Hawaii’s definition of good cause for the purposes of untimely MERF form filing is not consistent with the AFDC program. The Secretary’s delegation to Hawaii of the good cause definition is invalid to the extent that it allows Hawaii to exceed the scope of the Secretary’s initial authority to formulate the definition. Hawaii exceeded the scope of this authority in two specific ways when it restrictively defined good cause.
First, the Hawaii good cause definition is not consistent with the legislative purposes of the AFDC program, “WIN” work incentive programs, or MERF form filing deadlines. The goal of the AFDC program is to help AFDC families “attain or retain capability for the maximum self-support and personal independence consistent with the maintenance of continuing parental care and protection.” Figueroa v. Sunn, 884 F.2d at 1291 (quoting 42 U.S.C. § 601 (1982)). Earned income disregards provided by the WIN work incentive programs provide an “affirmative incentive to employment” by allowing working AFDC recipients to enjoy more fully the fruits of their employment. Heckler v. Turner, 470 U.S. 184, 191, 105 S.Ct. 1138, 1142, 84 L.Ed.2d 138 (1985). And while Congress enacted penalties for late MERF form filers out of a concern that late filing contributed to erroneous welfare payments, Congress expressly included the good cause exemption to provide a shield for innocent late filers. See H.R.Conf.Rep. No. 900, 96th Cong., 2d Sess., reprinted in 1980 U.S.Code Cong. & Admin.News 1584.4
Hawaii’s restrictive good cause definition thus undercuts Congress’s broad vision in the AFDC program of fostering self-sufficiency and personal independence. Hawaii’s restrictive good cause definition also conflicts with the Congressional mandate of providing an affirmative incentive to employment.
Second, the restrictive Hawaii good cause definition is inconsistent with the regulatory scheme developed by the Secretary to implement the AFDC program. Regulations promulgated by the Secretary specifically require states to “provide recipients an opportunity to show good cause for not filing a timely report of earnings.” 45 C.F.R. § 233.37(c) (1988). Hawaii’s restrictive definition of good cause can work to deprive the applicant of any realistic opportunity to present her case for good cause as required by the regulation.
The Hawaii good cause definition also conflicts with federal regulations which *1379provide that eligibility conditions may not be imposed arbitrarily or unreasonably. 45 C.F.R. § 233.10(a)(1) (1988).5 Federal regulations stress that “eligibility conditions must be applied on a consistent and equitable basis throughout the State.” 45 C.F.R. § 233.10(a)(1)(iv) (1988) (emphasis added).6
Case law has “erected a fundamental principle of AFDC jurisprudence: that the Social Security Act will not countenance the depriving of needy children benefits because of factors beyond their control and unrelated to need.” Simpson v. Miller, 535 F.Supp. 1041, 1050 (N.D.Ill.1982) (citing King v. Smith, 392 U.S. 309, 88 S.Ct. 2128, 20 L.Ed.2d 1118 (1968)). Hawaii’s restrictive good cause definition is unreasonable and results in inequitable treatment of employed AFDC recipients who have legitimate, good cause reasons for submitting late MERF form filings (in Vierra’s case, a late filing due to circumstances beyond her control). The state agency’s good cause definition is thus inconsistent with the federal regulatory scheme, as well as federal legislative intent.
The Secretary’s decision to delegate the definition of good cause for late MERF form filings is invalid to the extent that it allows the state to promulgate a rule inconsistent with federal legislative intent and regulations. We will not “rubberstamp ... administrative decisions that [are] inconsistent with a statutory mandate or that frustrate the congressional policy underlying a statute.” Bureau of Alcohol, Tobacco and Firearms v. Federal Labor Relations Authority, 464 U.S. 89, 97, 104 S.Ct. 439, 444, 78 L.Ed.2d 195 (1983) (quoting NLRB v. Brown, 380 U.S. 278, 291-92, 85 S.Ct. 980, 988-89, 13 L.Ed.2d 839 (1965)).
2. The Secretary’s “Approval” of the Good Cause Definition
In order for a state to receive federal funds under the AFDC program, the state must submit to the Secretary, and have the Secretary approve, “a plan for aid and services that complies with the requirements set forth by the AFDC legislation.” Figueroa v. Sunn, 884 F.2d at 1291. Because the Secretary approved Hawaii’s general AFDC plan, including the section defining good cause, the government argues that we should defer to this approval as part of our general deference to agency determinations and expertise.
We will not, however, defer to the Secretary’s tacit approval or interpretation of a regulation which is plainly erroneous or inconsistent with statutory and regulatory mandates. Simpson v. Hegstrom, 873 F.2d at 1297. For the reasons stated above, Hawaii’s good cause definition is inconsistent both with the AFDC legislation and with regulations promulgated by the Secretary to implement those provisions. The Secretary plainly erred in its approval of the Hawaii state plan to the extent that he approved Hawaii’s good cause definition in the context of untimely MERF form filing. We need not defer to this error.
3. Deference Due the State’s Exercise of Discretion
Because of the breadth of discretion generally granted to the states in the administration of the AFDC program, see Largo v. Sunn, 835 F.2d at 208, appellees argue that we should defer to Hawaii’s good *1380cause definition as a legitimate policy choice which furthers the specific Congressional purpose behind the earnings penalty sanction of § 602(a)(8)(B)(i)(III). We have already explained how Hawaii erred when it formulated an overly restrictive good cause definition. Nevertheless, the deference due a state’s policy determination is an issue distinct from those addressed above.
The state appellee characterizes Vierra’s loss of subsistence level benefits as the case of “a woman who tried to claim a reward too late.” The state then argues that this court is not free to craft its own regulation based upon judicial notions of what constitutes a “better” policy. The federal appellee agrees, as apparently did the district court, that Hawaii’s restrictive definition of good cause is a legitimate policy choice which we should not disturb.
The position that Hawaii’s good cause definition constitutes a legitimate state policy choice fails to consider the consistency and reasonableness of the state regulation in relation to the AFDC purpose of equita-bility in benefit determinations, and in relation to federal regulations which have been promulgated to implement that purpose. See 45 C.F.R. §§ 233.10(a)(1), 233.-10(a)(l)(iv), and 233.20(a)(l)(i). As pointed out above, the state may not promulgate AFDC regulations which are inconsistent with federal statutory and regulatory schemes.
The governments’ position also fails to address the proper role of judicial review of agency determinations. Under the Administrative Procedure Act, we are required to review agency policy for consistency with and reasonableness under the agency’s legislative mandate. 5 U.S.C. § 706(2)(C) (1977).7
Vierra does not request that we formulate our own version of what “good cause” should be in this context. She urges us to invalidate the state regulation which contradicts federal legislative policy choices and federal regulations which seek to implement that policy. The Hawaii good cause definition is the result of a series of unreasonable interpretations of the Congressional mandate to determine AFDC eligibility in an equitable and reasonable fashion, and is inconsistent with the federal regulatory scheme which implements the AFDC program. Thus no deference is due Hawaii’s good cause definition as a policy choice. We therefore grant Vierra’s request to invalidate the Hawaii good cause definition.
CONCLUSION
We find that the Hawaii Department of Social Services definition of good cause in H.A.R. section 17 — 621—40(d)(3) is invalid due to its inconsistency with federal statutory commands and federal regulations. The district court’s order granting summary judgment for the government is therefore REVERSED. Vierra’s summary judgment motion is hereby GRANTED.
. “[T]he State agency shall not disregard ... any earned income of [a recipient who] ... failed without good, cause to make a timely report (as prescribed by the State plan pursuant to paragraph (14)) to the State agency of earned income received in such month.” 42 U.S.C. § 602(a)(8)(B)(i)(III) (emphasis added).
. It is not uncommon for courts to invalidate state and federal agency regulations in the area of health and human services benefits. See, e.g., Citizens Action League v. Kizer, 887 F.2d 1003 (9th Cir.1989), cert. denied sub nom. Department of Health Services v. Citizens Action League, — U.S. -, 110 S.Ct. 1524, 108 L.Ed.2d 764 (1990) (reversing district court by ruling a California agency’s interpretation of "estate” within provision of Medicaid law was impermissibly broad as inconsistent with federal regulations, despite the fact that the interpretation was supported by the Secretary): Briggs v. Sullivan, 886 F.2d 1132, 1139 (9th Cir.1989) (rejecting deference to agency expertise in context of administrative remedy exhaustion "where a claimant’s interest in having a particular issue resolved promptly is so great that deference to the agency’s judgment is inappropriate”) (quoting Mathews v. Bldridge, 424 U.S. 319, 330, 96 S.Ct. 893, 900, 47 L.Ed.2d 18 (1976)); Figueroa v. Sunn, 884 F.2d 1290, 1292-93 (9th Cir.1989) (holding that the Hawaii Department of Social Services’s characterization of temporary disability benefits as unearned income violated Social Security Act purposes); Simpson v. Hegstrom, 873 F.2d 1294 (9th Cir.1989) (affirming district court judgment that Secretary’s interpretation of a regulation implementing AFDC “WIN” program was "unreasonable” and therefore invalid); Cervantes v. Sullivan, 719 F.Supp. 899 (E.D.Cal.1989), addendum at 724 F.Supp. 757 (E.D.Cal.1989) (invalidating Department of Health and Human Services regulation which counted garnished funds in determining supplemental security income as inconsistent with the statute).
. In fact, language in paragraph 14 authorizes the states to "select categories of recipients who may report at specified less frequent intervals upon a determination that to require individuals in such categories to report monthly would result in unwarranted expenditures for administration of this paragraph.” 42 U.S.C.A. § 602(a)(14). This concern with unwarranted administrative expenditures would seem to run counter to the government’s pursuit of Ms. Vier-ra in Federal Court for an alleged overpayment of $198.00.
. The House adopted the Senate’s inclusion of the good cause exemption in the effort to reverse the problems related to late reporting. The Senate bill provided that "the earnings disregards would not be applied to any earned income that is not reported on a timely basis (unless there is good cause).” H.R.Conf.Rep. No. 900, 96th Congress, 2d Sess., reprinted in 1980 U.S.Code Cong. & Admin.News 1584.
. "The groups selected for inclusion in the plan and the eligibility conditions imposed must not exclude individuals or groups on any arbitrary or unreasonable basis, and must not result in inequitable treatment of individuals or groups in the light of the provisions and purposes of the public assistance titles of the Social Security Act.” 45 C.F.R. § 233.10(a)(1) (1988) (emphasis added).
. The federal appellees argue that MERF filing requirements and good cause exemptions are factors independent of the general AFDC eligibility and benefit level determinations. Implied in such an argument is the notion that termination of benefits need not proceed in the same equitable and consistent manner as determination of eligibility in the first place, a notion plainly inconsistent with the requirements of due process as well as the Congressional mandate.
. "To the extent necessary to decision and when presented, the reviewing court shall decide all relevant questions of law, interpret constitutional and statutory provisions, and determine the meaning or applicability of the terms of an agency action. The reviewing court shall ... hold unlawful and set aside agency action, findings, and conclusions found to he ... in excess of statutory jurisdiction, authority, or limitations, or short of statutory right.” 5 U.S.C. § 706(2)(C).