The opinion of the court was delivered by
HUMPHREYS, J.S.C.(temporarily assigned).
The New Jersey Division of Medical Assistance and Health Services (“DMAHS”) has a policy of requiring a higher standard of proof of the timely filing of a Medicaid claim than would be required in “general business practice.” The Acting Director of DMAHS applied that policy and rejected a recommendation by Jaynee LaVecchia, Chief Administrative Law Judge (“CALJ”), that certain claims of plaintiff SSI Medical Services, Inc. (“SSI”) be allowed. The Acting Director followed the recommendation of the CALJ that other claims of plaintiff be rejected. Plaintiff appeals the Acting Director’s decision.
After a thorough review of the record and the briefs and arguments of counsel, we agree with the findings and recommendations of the CALJ in her comprehensive and well stated written opinion of March 24, 1994. We specifically do not agree with the DMAHS’s policy of requiring a higher standard of proof. We add the following with respect to the claims which the CALJ recommended be allowed.
I
The issue in this case is whether plaintiff submitted the claims in a timely manner. The CALJ, after hearing the witnesses and reviewing the evidence, found that the claims listed in Attachment A to her opinion had not been timely submitted because there had been no timely follow up inquiry by plaintiff. The CALJ found that the claims listed in Attachment B to her opinion should be allowed. Plaintiff had made a timely inquiry with respect to the Attachment B claims.
The Acting Director stated:
The Director REVERSES the recommended decision on the Attachment-B claims because he disagrees with the Chief ALJ’s findings and conclusions for two reasons.
The first reason is that the policy of the New Jersey Medicaid program has been that a provider of service must present “documentary evidence of filing” of the claims with the fiscal agent, Jewish Hospital and Rehabilitation Center v. DMAHS, 92 N.J.A.R.2d (DMA) 53, 58 [1992 WL 279813] (1992). As indicated in *187the holding of the above-cited case, this Division has historically required a higher standard for proof of timely filing of a claim than the general business practice with regard to processing and mailing set-forth in the line of cases on which the Chief ALJ relied in reaching her decision.
The reason for requiring a higher standard of proof concerning the timely filing of a Medicaid claim is two-fold. The first reason, which is not an issue in this case, is to protect the integrity of the Medicaid program which pays providers of service millions of dollars in both State and Federal funds. The second reason, which is in issue in this case, is to avoid a disallowance of the federal share of the Medicaid payments because a claim was not filed within twelve months from the date of service (42 CFR 447.45(d)) and to comply with the State legislative mandate set-forth in N.J.SA. 30:4D-7, that the Commissioner maximize federal funding.
The Director also rejects the Chief ALJ’s recommendation to process the Attaehment-B claims for payment because the Petitioner’s proofs do not satisfy the requirements to create the presumption of receipt as set-forth in the line of cases relied on by the Chief ALJ.
The Acting Director also concluded that ample proof had been presented to rebut any presumption of receipt. In addition, he said that contrary to the CALJ’s finding, a claimant had only one year, not one year and ninety days to submit a claim. Finally, he concluded that the evidence was not sufficient to support a conclusion that the “Medicaid claims processing unit at Prudential was a ‘black hole’ that routinely lost claims.”
II
We do not agree with the Acting Director that a Medicaid claimant must meet a higher standard of proof. We are mindful that public money is involved and care must be taken to protect against corruption, fraud and improvidence. However, there is no indication in this record of any corruption, fraud or improvidence. The Acting Director admitted in his opinion that the integrity of the Medicaid Program is not in issue here.
Those who have valid claims against the government ordinarily need not bear a heavier burden in proving those claims than claimants against private parties. Justice Holmes’ oft quoted statement that “[m]en must turn square corners when they deal with the Government,” Rock Island, A. & L.R. Co. v. United States, 254 U.S. 141, 143, 41 S.Ct. 55, 56, 65 L.Ed. 188, 189 (1920), *188has in recent times been transformed into “[i]n dealing with the public, government must ‘turn square comers.’ ” F.M.C. Stores Co. v. Borough of Morris Plains, 100 N.J. 418, 426, 495 A.2d 1313 (1985) (citation omitted). Furthermore, in dealings with the public, government may not “exploit litigational or bargaining advantages that might otherwise be available to private citizens.” W.V. Pangborne & Co. v. New Jersey Dep’t of Transp., 116 N.J. 543, 561, 562 A.2d 222 (1989). Government must also “adhere to strict standards in its contractual dealings.” Id. at 562, 562 A.2d 222. The DMAHS’s “policy” that those who submit claims to it must adhere to a higher standard of proof does not conform to modern concepts of the duty of government to the public which it serves.
The DMAHS’s policy is also contrary to the general rule that the traditional preponderance of the evidence standard applies to the vast majority of administrative agency matters. 2 Davis & Pierce, Administrative Law Treatise § 10.7 (3d ed. 1994); Fairfax Hospital Ass’n, Inc. v. Califano, 585 F.2d 602, 611-12 (4th Cir.1978). See also Bender v. Clark, 744 F.2d 1424 (10th Cir.1984) (Government’s interest in implementing congressional leasing policy on federal lands did not warrant placing a higher burden of proof on a challenger to a government determination regarding that land). Exceptions are those rare cases in which the Constitution or a statute requires a higher standard. See Administrative Law Treatise, supra, at § 10.7. No such constitutional or statutory requirement is present here. Nor has the agency implemented its policy by adopting a rule or regulation thereby giving fair notice of its policy to those who file claims with it. See Metromedia, Inc. v. Director, Div. of Taxation, 97 N.J. 313, 331, 478 A.2d 742 (1984) (general administrative policies should be implemented by rules, not individual adjudications).
Furthermore, we understand from oral argument that federal funding will not be jeopardized if we uphold the plaintiffs claims. A Medicaid agency is permitted to “make payments at any time in accordance with a court order, to carry out hearing decisions or *189agency corrective actions taken to resolve a dispute____” 42 C.F.R. § 447.45(d)(4)(iv) (1990).
Thus, resolution of the factual issues here must be governed by the usual standards of proof. If the proofs establish by a preponderance of the evidence that plaintiff submitted these claims in a timely fashion, then the claims should be processed for payment.
Ill
The CALJ conducted a plenary hearing. In her written opinion of Mareh 24,1994, she made a thorough analysis of the testimony and documentary evidence. She concluded that SSI mailed the claims to Prudential and that the mailing raised a presumption of receipt.
The evidence clearly merited the CALJ’s finding that the claim forms in question were mailed by plaintiff to Prudential. The following evidence was presented by testimony and affidavits. The Medicaid claim forms were prepared by Renee Mills, an employee of plaintiff. Photocopies of the forms were made for plaintiffs files and the originals placed in a pile for submission to the fiscal agent of DMAHS. After some fifty to seventy-five forms were collected, Ms. Mills personally addressed the mailing envelopes. She included plaintiffs return address and the address for delivery. The forms were then deposited in plaintiffs mail baskets. Plaintiffs mail room clerks were instructed to collect mail from each of the mail baskets on a daily basis. Once collected, the individual pieces of mail were stamped with the appropriate amount of postage using plaintiffs postage meter. Each envelope was then placed in a bin obtained by plaintiff from the U.S. Postal Service. Every weekday, other than federal holidays, a U.S. Postal Service employee would arrive at plaintiffs offices in the early evening and collect the mail for delivery. During Ms. Mills’ five years with plaintiff, no claim form had been returned to her by the U.S. Postal Service for any reason.
Ms. Mills asserted that Prudential frequently misplaced submitted claim forms and had “poor document management.” She said *190that sometimes plaintiff had to wait a few months after each submission and then, if payment had not been received, resubmit the forms under the assumption that Prudential had lost the original submission. She said that Prudential’s inefficiencies were such that claim forms often “had to be resubmitted more than once, and sometimes several months expired before SSI could determine whether it was necessary for an additional copy of a claim form to again be submitted.”
These problems were “largely cured,” she said, when UNISYS succeeded Prudential as the fiscal agent. She said that Prudential had a “chronic problem of losing submitted claim forms” and that some UNISYS employees “have even referred to Prudential as a ‘black hole’ with respect to its ability to properly process claims information.”
Ms. Mills further asserted that the claim forms at issue have submission dates which were “relatively evenly scattered throughout the year.” This, she said, refutes any inference that plaintiff failed to submit one envelope with a substantial group of claim forms in it. Ms. Mills also said that “DMAHS has accepted and paid the vast majority of the claim forms that SSI submitted during each month in 1991, thus indicating that Prudential in fact received the claim forms that DMAHS is now disputing as being untimely filed.” Ms. Mills also submitted claim forms to other states. She said that only in New Jersey was the resubmission of claim forms “consistently and regularly” requested.
The CALJ found that the claims in Attachment B had “a timely date of original submission” within a month or two following the period of service. The CALJ found “documentary evidence of a timely original billing completed and mailed at SSI in accordance with office procedure and custom.” In addition, each of the claims in Attachment B has a “resubmitted billing which occurred within either the initial twelve month period, or during the additional ninety day period allowed for follow-up inquiry pursuant to N.J.A.C. 10:49-7.2(g).”
*191Proof of mailing can be established by evidence of habit or routine practice. See Biunno, Current N.J. Rules of Evidence, Comment 1 on N.J.R.E. 406(a) (1994). Such evidence need not be corroborated. Ibid. Evidence of specific instances of conduct may prove habit or routine practice if there is a sufficient number of such instances. N.J.R.E. 406(b).
“Evidence of office procedure can give rise to the presumption of mailing.” Cwiklinski v. Burton, 217 N.J.Super. 506, 510, 526 A.2d 271 (App.Div.1987). Further, the fact of mailing may be established “by evidence of a custom with respect to the mailing of letters, coupled with the testimony of the person whose duty it is to perform or carry out the custom.” Ibid, (quoting Cook v. Phillips, 109 N.J.L. 371, 373, 162 A. 732 (E. & A.1932)).
As stated in 58 Am.Jur.2d Notice § 47 (1989):
Personal knowledge ... is required only to establish regular office procedure, not the particular mailing.
[ ]In large offices that handle a volume of mail, direct proof with respect to a particular letter is impractical. In such cases, proof of settled custom and usage of the sender’s office, regularly and systematically followed in the transaction of business may suffice as proof of mailing.
In Bruce v. James P. MacLean Firm, 238 N.J.Super. 501, 507, 570 A.2d 49 (Law Div.), aff'd o.b., 238 N.J.Super. 408, 570 A.2d I (App.Div.1989), testimony as to office policy by the people actually charged with the task of mass mailing of notices was held sufficient to prove mailing.
Here, there was detailed and specific evidence by testimony and affidavits from the persons who were responsible for office procedures involving the mailing of these claim forms. The claim forms themselves and other evidence as indicated in this opinion add further support to the CALJ’s finding that the claims in Attachment B were mailed to Prudential. In sum, the evidence viewed as a whole convincingly supports the CALJ’s factual finding that these claims were properly mailed to Prudential in a timely manner.
*192Proper mailing gives rise to a presumption, namely that “mail matter correctly addressed, stamped and mailed was received by the party to whom it was addressed, which presumption is rebut-table and may be overcome by evidence that the notice was never in fact received.” Szczesny v. Vasquez, 71 N.J.Super. 347, 354, 177 A.2d 47 (App.Div.1962). See Waite v. Doe, 204 N.J.Super. 632, 636, 499 A.2d 1038 (App.Div.1985), certif. denied, 102 N.J. 398, 508 A.2d 256 (1986). The evidence not only supports the CALJ’s finding that the presumption of receipt was unrebutted but persuasively supports her finding that Prudential received the forms and then lost them. There was unrebutted testimony that many claim forms were “lost” at Prudential and had to be resubmitted. In addition, the CALJ found that the “random dates of the claim forms in issue are a factor in SSI’s favor—no batched claims were lost here—only individual claim forms occurring sporadically over more than a year in time.” The CALJ reasonably inferred that “discrete claims can and probably were lost, not that a whole batched grouping of claim forms were never mailed by SSL”
The record was more than sufficient for the CALJ to give little weight to “generalized statements” that DMAHS’s files had been searched at Prudential without finding the claims in question. Ample support in the record can be found for the CALJ’s statement that she had “no confidence that the Prudential material accurately reported all claims sent to it.”
Furthermore, there is no indication that plaintiff manufactured the claims. As the Acting Director conceded, the “integrity of the Medicaid Program” is “not an issue in this case.”
The case boils down to this: either (1) Prudential lost the Attachment B claim forms, or (2) plaintiff did not submit or resubmit them. This wholly factual question is best resolved by the person who heard the facts. This is not a case such as Adamar v. Dep’t of Law, 250 N.J.Super. 275, 593 A.2d 1237 (App.Div.1991) relied on by our dissenting colleague. In Adamar, the facts were “either stipulated or undisputed.” Id. at 281, 593 *193A.2d 1237. The central issue was whether the plaintiffs admitted conduct violated the regulations of the Casino Control Commission. The Commission’s experience and expertise were important factors in deciding this basically non-factual issue.
In the present case, the facts and the inferences to be drawn therefrom are in sharp dispute. Under these circumstances, we need not defer to the factual findings of one who did not hear the evidence. As stated by the New Jersey Supreme Court in Clowes v. Teminix Intern., Inc., 109 N.J. 575, 587-88, 538 A.2d 794 (1988):
As a general rule, the reviewing court should give “due regard to the opportunity of the one who heard the witnesses to judge of their credibility * * * and * * * [give] due regard also to the agency’s expertise where such expertise is a pertinent factor.” Close v. Kordulak Bros., [] 44 N.J. [589, 599 [210 A.2d 753] (1965) ]. In this ease, however, the Appellate Division need not have deferred to the Director on the issue of the credibility of the witnesses. Both the court below and the Director based their respective reviews of the transcripts and documentary evidence submitted by the parties. It was the AL J, and not the Director, who heard the live testimony, and who was in a position to judge the witnesses’ credibility. As noted above, the Director rejected many of the ALJ’s recommended findings of fact. Under these circumstances a revieu/ing court need give no deference to the agency head on the credibility issue, (emphasis added).
See also Steinmann v. State, Dep’t of Treasury, 116 N.J. 564, 575-76, 562 A.2d 791 (1989).
In sum, the factual findings of the CALJ are compellingly supported by the record, to wit that plaintiff timely submitted the Attachment B claims to Prudential, the agency’s fiscal agent, and that Prudential probably lost them. A government agency should not be permitted to disallow a valid claim against it by taking advantage of the mistakes and inefficiency of its fiscal agent. Rejection of plaintiffs claims in the face of these clearly warranted factual findings would be a miscarriage of justice.
We affirm the decision of DMAHS as to the claims disallowed by the CALJ and reverse the DMAHS decision as to the claims allowed by the CALJ.