This appeal is from the judgment of sentence imposed after appellee entered a negotiated plea to burglary. Appellant, the Commonwealth, contends that (1) the court below erred in refusing to include appellee’s juvenile adjudications in computing his prior record score; and (2) assuming that appellee’s prior record score was correctly computed, the totality of the circumstances indicates that the sentencing court imposed an unreasonably lenient sentence. Finding appellant’s first contention to be without merit and the second to have been waived, we affirm the judgment of sentence.
On June 29, 1984, appellee, Andrew Tilghman, pled guilty to a charge of burglary. The guilty plea was negotiated only to the extent that it was agreed that the Commonwealth would recommend that appellee be sentenced in the mitigated minimum range. Sentencing was then deferred.
On December 13, 1984, appellee appeared for sentencing. The parties agreed that the offense gravity score for the burglary offense was “5”, but disagreed as to whether a prior juvenile adjudication of involuntary deviate sexual *331intercourse could be used in computing appellee’s prior record score. The prior record score was “0” without inclusion of the juvenile adjudication and “3” with such inclusion. The sentencing court determined that it was proper to use the prior juvenile adjudication in computing appellee’s prior record score. It then sentenced appellee to 4 to 23 months imprisonment, a sentence in the mitigated range applicable to a defendant with a prior record score of “3” and an offense gravity score of “5.”
Appellee filed a timely motion to modify sentence on December 21, 1984. On the same date, the court below filed an order vacating the sentence it had imposed. The sentencing court held a hearing on February 21, 1985, at which time it reversed its earlier decision, and held that appellee’s prior juvenile adjudication could not be considered in computing his prior record score. The court then sentenced appellee to 24 months probation, a sentence in the mitigated range applicable to a defendant with a prior record score of “0” and an offense gravity score of “5.”
On March 4, 1985, the Commonwealth filed a motion to modify sentence which the court below denied without a hearing. This appeal timely followed.
Appellant- initially argues that, although the sentencing court purported to sentence appellee within the sentencing guidelines,1 it applied the guidelines erroneously when it did not include in its computation of appellee’s prior record score his juvenile adjudication of delinquency which had been based on the commission of the felony of involuntary deviate sexual intercourse. We disagree.
Initially, we note that a party may not appeal as of right the discretionary aspects of a sentence for a felony or a misdemeanor, but may only request this Court to allow an *332appeal on the basis that there is a substantial question that the sentence imposed is not appropriate under the Sentencing Code. Commonwealth v. Easterling, 353 Pa.Super. 84, 509 A.2d 345 (1986); 42 Pa.C.S. § 9781(b). In Easterling, a panel of this Court held that there is a substantial question that the sentence is inappropriate if, after a brief review of the record, we are not substantially convinced that one of the following three circumstances is not before us:
(1) the sentencing court purported to sentence within the sentencing guidelines but applied the guidelines erroneously;
(2) the sentencing court sentenced within the sentencing guidelines but the case involves circumstances where the application of the guidelines would be clearly unreasonable; or
(3) the sentencing court sentenced outside the sentencing guidelines and the sentence is unreasonable.[2]
*333Here, the sentencing court, while purporting to sentence within the guidelines, refused to consider a prior adjudication of delinquency of appellant in computing appellant’s prior record score despite the fact that the adjudication was of a type required by § 303.7(b) of the guidelines to be included in a calculation of a prior record score.3 These circumstances convince us that there is a substantial question at least as to whether the sentencing court erroneously applied the guidelines and thus as to whether the sentence imposed in this case is appropriate. Therefore, we shall accept the Commonwealth’s appeal.
Although the sentencing guidelines do provide in § 303.7 for inclusion of certain juvenile adjudications of delinquency in the computation of a defendant’s prior record score, the basis for the decision of the court was that the Pennsylva*334nia Sentencing Commission exceeded the authority granted it by the Legislature by providing for such inclusion. The Legislature authorized the creation of the Pennsylvania Commission on Sentencing in 42 Pa.C.S. §§ 2151-53 and in § 2154 specifically directed the Commission to adopt sentencing guidelines as follows:
Adoption of guidelines for sentencing
The Commission shall adopt guidelines for sentencing within the limits established by law which shall be considered by the sentencing court in determining the appropriate sentence for felonies and misdemeanors committed by a defendant. The guidelines shall:
(1) Specify the range of sentences applicable to crimes or a given degree or gravity.
(2) Specify a range of sentences of increased severity for defendants previously convicted of a felony or felonies or convicted of a crime involving the use of a deadly weapon.[4]
(3) Prescribe variations from the range of sentences applicable on account of aggravating or mitigating circumstances.
(emphasis added).
Before discussing the issue raised by appellant, we think it important first to make clear what the Commonwealth does not contend. It does not contend that the term “convicted” as used in § 2154(2) encompasses juvenile adjudications of delinquency as well as adult convictions. As part of its determination that the Sentencing Commission lacked the power to include juvenile adjudications in the computation of the prior record score, the sentencing court held that the Legislature in using the words “previously convicted” was not also referring to persons who have been previously adjudicated delinquent in a juvenile proceeding. It based this holding on its reading of the Juvenile Act, 42 Pa.C.S. §§ 6301-65, and of caselaw and on an application of general principles of statutory construction. As the Commonwealth *335has not challenged this holding on appeal, we need not address whether a juvenile adjudication constitutes a prior conviction, or whether there exists any interrelationship between § 2154(2) and the Juvenile Act, 42 Pa.C.S. §§ 6301-65.
What the Commonwealth does contend is that § 2154(2) merely sets forth the minimum criteria that the Sentencing Commission was required to consider and did not constrain the Commission to include consideration of only the specified criteria. We believe the Commonwealth’s position is contrary to the relevant principles of statutory construction.
First, the limits of the power conferred on an administrative agency must be strictly construed. Murphy v. Commonwealth, 506 Pa. 549, 486 A.2d 388 (1985).
“The principle guiding to decision is this: The power and authority to be exercised by administrative commissions must be conferred by legislative language clear and unmistakable. A doubtful power does not exist. Such tribunals are extrajudicial. They should act within the strict and exact limits defined.” Green v. Milk Control Comm’n, 340 Pa. 1, 3, 16 A.2d 9 (1940).
See also Volunteer Firemen’s Relief Ass’n v. Minehart, 425 Pa. 82, 227 A.2d 632 (1967); Community College of Delaware County v. Fox, 20 Pa.Cmwlth. 335, 342 A.2d 468 (1975). Only those powers within the legislative grant, either express or necessarily implied, can be exercised by the administrative body.
Pennsylvania Human Relations Commission v. St. Joe Minerals Corp., 476 Pa. 302, 310, 382 A.2d 731, 735-36 (1978).
Under this principle of statutory construction, the Commission had the power to specify a range of sentences of increased severity based on criteria not specified in § 2154(2) only if such a power was expressly within or necessarily implied by the legislative grant. We think it clear from a reading of § 2154 that it neither expressly grants nor necessarily implies that the Commission had the power in question. Thus, the conclusion we must reach *336from the foregoing principle is that the Commission did not have the power to specify a range of sentences of increased severity based on criteria not specified in § 2154(2). In other words, the Sentencing Commission lacked the power to adopt guidelines in which the prior record score was computed on the basis of anything other than prior convictions of felonies or convictions of a crime involving the use of a deadly weapon.
This conclusion is also consistent with another principle of statutory construction, the general statutory maxim, ex-pressio unius est exclusio alterius. “As the maxim is applied to statutory interpretation, where ... [the] things to which it refers are designated, there is an inference that all omissions should be understood as exclusions/’ Sutherland, Stat. Const. § 47.23; see also, Gaebel v. Thornbury Township, Delaware County, 8 Pa.Cmwlth. 379, 303 A.2d 57 (1973). Thus, since § 2154(2) designated previous felony convictions and convictions of a crime involving the use of a deadly weapon as those things for which a range of sentence of increased severity could be specified, there is an inference that the Legislature intended that no other considerations could be so used.5
In an attempt to circumvent this basic maxim, the Commonwealth argues that the Legislature demonstrated that § 2154(2) was intended to include prior juvenile adjudications in the prior record score, as the Legislature did not reject that portion of the sentencing guidelines when the guidelines were submitted to the Legislature by the Commission. However, 42 Pa.C.S. § 2155 provided that the guidelines would become law if not rejected by concurrent legislative resolution within 90 days of their submission. The guidelines were submitted to the Legislature on January 23, 1982, and were approved by the Senate on April 20, 1982. The House took no action with respect to the guidelines although, in any event, it was powerless to stop the guidelines from becoming effective once the Senate had *337approved them. On April 23, 1982, the sentencing guidelines became effective in Pennsylvania. We believe it would be inappropriate to ascribe a legislative intent to the. fact that the Legislature did not reject that portion of the guidelines dealing with prior juvenile adjudications when the House did not even vote on the matter. The Commonwealth’s position here simply fails to persuade.6
*338We thus find no merit in the Commonwealth’s contention that § 2154(2) merely set forth the minimum criteria that the Sentencing Commission was required to consider. Therefore, the Commonwealth has advanced no basis on which we could conclude that the sentencing court erred in holding that the Sentencing Commission had no power to specify a range of sentences of increased severity for defendants previously adjudicated delinquent and thus erred in not including appellee’s prior adjudication in his prior record score.
With respect to the Commonwealth’s second contention on appeal, we must, again, make clear what the Commonwealth does not contend. It does not contend that prior adjudications of delinquency may be used as an “aggravating circumstance”, under § 2154(3), to place a sentence in the aggravated range. The sentencing court held that prior juvenile adjudications could not be considered as an “aggravated circumstance”, but could only be considered in deciding where within an otherwise appropriate range to sentence a defendant. The Commonwealth has not challenged this holding on appeal.7
What the Commonwealth does contend is that, even if appellee’s prior record score was computed correctly, and thus his sentence was within the mitigated range of the guidelines, the sentence was unreasonably lenient under the totality of the circumstances. The Commonwealth argues that any minimum sentence of less than four months impris*339onment would be unreasonable.8 However, except for the claim that the court below applied the guidelines erroneously, see 42 Pa.C.S. § 9781(c)(1), the only claim made by the Commonwealth in its motion to modify sentence was that the sentencing court had sentenced appellee outside the sentencing guidelines and that the sentence unreasonably deviated from the guidelines, see 42 Pa.C.S. § 9781(c)(3). It is well-settled that sentencing issues not raised in a motion to modify sentence are waived. Commonwealth v. Duffy, 341 Pa.Super. 217, 491 A.2d 230 (1985); Commonwealth v. Warden, 335 Pa.Super. 315, 484 A.2d 151 (1984). Therefore, we conclude that the Commonwealth has waived its claim that a sentence in the mitigated range is unreasonably lenient.9
Finding no merit to either of the Commonwealth’s claims, we will affirm the judgment of sentence. Judgment of sentence affirmed.
ROWLEY, WIEAND, MONTEMURO, BECK, POPOVICH and JOHNSON, JJ., join. CIRILLO, President Judge, files a concurring statement. TAMILIA, J., files a dissenting opinion.. Pursuant to 42 Pa.C.S. § 2155 and 204 Pa. Code § 303.1(d), the sentencing guidelines promulgated by the Pennsylvania Commission on Sentencing, see 204 Pa. Code §§ 303.1-303.9, reprinted following 42 Pa.C.S. § 9721, became effective on July 22, 1982 as to all offenses committed on or after that date. Since the offense involved in the instant case was committed on January 5, 1984, the guidelines arc applicable to this case.
. The Easterling court defined a substantia] question in this manner because, under 42 Pa.C.S. § 9781(c), a finding that any one of these circumstances exists empowers this Court to vacate a judgment of sentence and remand for resentencing. We note, however, that 42 Pa.C.S. § 9721(b) provides that:
In selecting from the alternatives set forth in subsection (a) the court shall follow the general principle that the sentence imposed should call for confinement that is consistent with the protection of the public, the gravity of the offense as it relates to the impact on the life of the victim and on the community, and the rehabilitative needs of the defendant. The court shall also consider any guidelines for sentencing adopted by the Pennsylvania Commission on Sentencing and taking effect pursuant to section 2155 (relating to publication of guidelines for sentencing). In every case in which the court imposes a sentence for a felony or misdemeanor, the court shall make as a part of the record, and disclose in open court at the time of sentencing, a statement of the reason or reasons for the sentence imposed. In every case where the court imposes a sentence outside the sentencing guidelines adopted by the Pennsylvania Commission on Sentencing pursuant to section 2154 (relating to adoption of guidelines for sentencing) and made effective pursuant to section 2155, the court shall provide a contemporaneous written statement of the reason or reasons for the deviation from the guidelines. Failure to comply shall be grounds for vacating the sentence and resentencing the defendant, (emphasis added).
Thus, this Court may also vacate a judgment of sentence and remand for resentencing where a sentencing court fails to comply with the requirements of § 9721(b). Under the rationale of Easterling, we *333thcrefore believe that there is also a substantial question that the sentence imposed is inappropriate if one of the requirements of § 9721(b) is before us.
. At the time the sentencing court reached its decision, § 303.7 stated the following in relevant part:
(b) Adjudications of delinquency and other prior convictions.
(1) The offenses scored in this subsection are as follows:
(i) All prior convictions for felonies and all prior convictions for the weapons misdemeanors listed in subsection (a)(3).
(ii) All prior juvenile adjudications of delinquency where there was an express finding that the adjudication was based on the commission of a felony or one of the weapons misdemeanors listed in subsection (a)(3) where the adjudication occurred on or after the defendant’s 14th birthday.
Section 303.7 was amended, effective June 5, 1986, and now provides the following in relevant part:
(b) Adjudications of delinquency and other prior convictions.
(1) The offenses scored in this subsection are as follows:
(i) All prior convictions for felonies and all prior convictions for the weapons misdemeanors listed in subsection (a)(3).
(ii) Each prior offense which resulted in a juvenile adjudication of delinquency where:
(A) there was an express finding by the juvenile court that the adjudication was for a felony or one of the weapons misdemeanors listed in (a)(3),
(B) the offense occurred on or after the defendant’s 14th birthday, and
(C) the currently sentenced offense is a felony.
No other juvenile adjudication of delinquency shall be counted in the prior record score.
. This provision led the Commission to adopt the “prior record score” set forth at 204 Pa. Code § 303.7.
. In effect, the principle of statutory construction applicable to administrative commissions is simply a particular example of the principle of expressio unius est exclusio alterius.
. The dissent addresses the implications of Act 165 of 1986: Act of December 11, 1986, which has amended both 42 Pa.C.S. § 2154 and 204 Pa.Code § 303 in order to permit the inclusion of juvenile adjudications in the computation of prior record scores. The dissent contends that the amendments, as well as Chairman O’Brien’s commentary, support its view that we are misconstruing the legislature’s original intent, prior to amendment.
As the dissent points out, Act 165 has amended the definition of "prior conviction" at 204 Pa.Code § 303.7(g). However, the legislature has also amended the Commission’s enabling legislation at 42 Pa.C.S. § 2154 as follows:
§ 2154. Adoption of guidelines for sentencing.
(a) ... The guidelines shall
(2) Specify a range of sentences of increased severity for defendants previously convicted of or adjudicated delinquent for one or more misdemeanor or felony offenses committed prior to the current offense. For purposes of this section “previously convicted or adjudicated delinquent"shall include any finding of guilt or adjudication of delinquency whether or not sentence has been imposed or disposition ordered prior to the commission of the current offense.
Purdon’s Pennsylvania Legislative Service, Session of 1986, 170th Session, Acts 1986-144 to 1986-213, at pp. 105-06. (Emphasis in the original).
Chairman O’Brien’s commentary on the above amendment states that "(S)everal court opinions have questioned the authority of the Commission to include ... juvenile adjudications of delinquency in the prior record score ... ”, noting the opinion in this matter. Pennsylvania Bulletin, Vol. 16, No. 51, Dec. 20, 1986, p. 4867, Chairman O’Brien continues by noting that “Act 165 of 1986 provides explicit authority" for the inclusion. Id. These statements, in combination with the amendment of 42 Pa.C.S. § 2154(a)(2), contrary to the assertions of the dissent, do not lead to the unavoidable conclusion that we are misconstruing legislative intent. Rather, it supports the position we have taken that the original enabling act, in the absence of explicit authority, does not permit the inclusion of juvenile adjudications in the computation of prior record scores. If the original enabling act permitted their inclusion, the legislature would have merely needed to re-define "prior conviction” to include juvenile adjudications, and would not have been compelled to alter the Commission’s enabling legislation.
*338Moreover, Chairman O’Brien’s commentary indicates that the redefinition of "prior conviction” is not in response to our opinion in this matter, but, rather, is merely intended to incorporate the view espoused in Commonwealth v. Wolfe, 349 Pa.Super. 415, 503 A.2d 435 (1986) and Commonwealth v. Mourar, 349 Pa.Super. 583, 504 A.2d 197 (1986), that prior convictions must, in order to be includable in a defendant’s prior record score, antedate the commission of the offense upon which sentence is currently being imposed. Id.
. Since the Commonwealth has not questioned this holding on appeal, a decision as to whether the holding is inconsistent with this Court’s decision in Commonwealth v. Lupatsky, 341 Pa.Super. 338, 491 A.2d 845 (1985) must await another day. In Lupatsky, we held that while summary offenses may not be included in a prior record score • computation, they can be used as an aggravating circumstance.
. A minimum sentence of four months imprisonment would be in the standard (minimum) range of 0-12 months imprisonment for an offense gravity score of "5” and a prior record score of "0”.
. Appellee argues that the Commonwealth should be estopped from advancing its claim because it had agreed to recommend a sentence in the mitigated range. Given our disposition of the Commonwealth’s claim, we need not resolve that question. Our disposition also makes it unnecessary to resolve the rather interesting question of whether under § 9781(c)(2), we may vacate a sentence and remand for resentencing where a sentence within one of the applicable guideline ranges would be clearly unreasonable, but a sentence within either of the other two applicable ranges would not be clearly unreasonable.