PER CURIAM.
Petitioner Elizabeth R. Steinmann appeals from a final determination of the New Jersey Teachers’ Pension and Annuity Fund (TPAF) denying her request to convert her ordinary disability retirement plan to an early service retirement. On appeal she contends that TPAF’s failure to render its final determination within 45 days of the ALJ’s initial decision, which recommended approval of petitioner’s request, made the ALJ’s recommendation a final decision pursuant to N.J.S.A. 52-.14B-10(c). In the alternative, she argues that TPAF’s denial of her request to convert was arbitrary, capricious and unreasonable. We reject both contentions and now affirm.
Petitioner enrolled in TPAF when she began her teaching career on September 1, 1957. Her membership continued until retirment in March 1983. Petitioner sustained work-connected injuries in April 1981 and filed a petition for workers’ compensation benefits. On January 81, 1983 she applied to TPAF for accidental disability retirement. Prior to filing the application, petitioner received a “benefits” booklet from TPAF which described eligibility requirements for accidental disability retirement as well as ordinary disability retirement. It also described eligibility requirements for early retirement benefits, including entitlement to full benefits upon 25 years of service, regardless of age. The book also explained that if the retiree:
... is receiving periodic benefits under Workmen’s Compensation, the actuarial equivalent of such benefits remaining to be paid will reduce the pension portion of his allowances.
On petitioner’s application for accidental disability benefits she was asked whether she had filed for workers’ compensation benefits, and if so, what benefits she was then receiving. The application also noted:
... see benefit booklet for [workers’ compensation benefits] effect on retirement allowance.
Petitioner disclosed on the application that she had filed a compensation claim and was receiving $58 temporary benefits weekly.
On December 19, 1983, petitioner’s application for accidental disability retirement was denied. However, pursuant to N.J. S.A. 18A:66-39b, TPAF granted her ordinary disability retirement benefits effective March 1, 1983. On February 7, 1984 the Division of Pensions advised petitioner of her option to change from an option 1 allowance which paid $800.72 monthly to a maximum allowance of $908.57. The notice also contained the following reminder:
Please note that if you are receiving any periodic Worker’s Compensation payments after the effective date of your retirement, your retirement allowance could be subject to a reduction. You must advise this office if and when you receive any Worker’s Compensation Benefits.
On February 18, 1984 petitioner elected the maximum allowance.
On July 10, 1984 petitioner recovered a workers’ compensation award of partial permanent benefits totalling $44,775. She thereupon notified TPAF of the award. On January 7,1985 she wrote to TPAF with the following request:
It is my understanding that my ordinary disability pension is not subject to any offset. If I am not correct in this matter, please change my pension to years in service.
The Division of Pensions responded on September 25, 1985, advising petitioner that her monthly allowance was being reduced to $559.88 per month because of the workers’ compensation set-off. She was also advised that she could not convert to an early retirement plan because TPAF had already approved the ordinary disability retirement.
On November 7, 1985 petitioner made formal application to TPAF for a conversion to a early retirement plan. Under that plan, petitioner would have received $752.93 monthly instead of the reduced amount of $559.88. TPAF denied the request, stating that once a retirement plan became effective, “the choice is irrevocable.” Petitioner appealed.
In his initial decision of November 17, 1986, the AU recommended reversal, concluding that TPAF had not dealt fairly with petitioner in failing to apprise her of her right to take early retirement in lieu of ordinary disability when her accidental disability claim was denied. The judge concluded that petitioner had demonstrated the requisite good cause and reasonable diligence to permit reopening of the retirement plan and conversion to an early retirement plan.
TPAF’s time period for the rendering of final decision was extended by the OAL until January 8, 1987. On that date TPAF rejected the ALJ’s recommendations and denied petitioner’s conversion request by a unanimous vote. On March 5, 1987 TPAF made its written findings. It concluded that petitioner knew at the time she accepted ordinary disability retirement that the benefits would be subject to a workers’ compensation set-off, that she also then knew she was eligible for the early retirement plan. It also found that since petitioner’s ordinary disability retirement was being granted under N.J.S.A. 18A:66-39 upon the denial of her accidental disability applica tion, it had no obligation to advise her of the early retirement plan option.
We reject petitioner’s procedural argument that TPAF failed to render a decision within 45 days as mandated by N.J.S.A. 52:14B-10c. That provision states that the agency shall adopt, reject or modify the AU’s recommendations no later than 45 days after receipt, and if the agency fails to do so, the AU’s decision shall be deemed adopted as the final decision of the agency. Here, the OAL extended the time period for TPAF’s decision until January 8, 1987, and on that date the board unanimously rejected the ALJ’s recommendation. N.J. S.A. 52:14B-10d requires that “[a] final decision or order adverse to a party in a contested case shall be in writing or stated in the record.” TPAF’s decision was “stated in the record” on January 8, 1987, within the time period as extended by the OAL. While it is true that for a decision to become effective, N.J.S.A. 52:14B-10(e) requires that it be delivered or mailed to the parties, the provision contains no explicit time constraint. See Belleville v. Coppla, 187 N.J.Super. 147, 152 (App.Div.1982). TPAF’s written findings were prepared on March 5, 1987 and sent to petitioner’s attorney on March 6, 1987. We are entirely satisfied that the findings supporting the decision were made within a reasonable period of time after TPAF made its decision. See id. Further, there is absolutely no showing that petitioner was in any way prejudiced by the two-month delay. In the circumstances, we see no basis to invalidate its action on this procedural ground.
We also reject petitioner’s contention that TPAF’s rejection of her conversion request was arbitrary, capricious and unreasonable. We are sensitive to the fact that petitioner has contributed to TPAF as a participating member for 25 years and are sympathetic to her efforts in securing the most advantageous retirement plan available. Indeed, if we were establishing regulations de novo, we might conclude that retirement plans could be reopened at any time to provide the maximum benefits available to retirees.
However, our role in reviewing an agency’s decision is narrowly circumscribed. Ordinarily, we will reverse the decision only if it is arbitrary, capricious or unreasonable or it is not supported by substantial credible evidence in the record as a whole. Henry v. Rahway State Prison, 81 N.J. 571, 579-580 (1980); Mayflower Securities v. Bureau of Securities, 64 N.J. 85, 92-93 (1973). Moreover, we are not at liberty to substitute our judgment for that of the administrative agency, see Dougherty v. Human Services Dep’t., 91 N.J. 1, 6 (1982), and we must be mindful that a presumption of reasonableness attaches to the agency’s action. Gerba v. Public Employees’ Retirem. Sys. Trustees, 83 N.J. 174, 189 (1980); Boyle v. Riti, 175 N.J.Super. 158, 166 (App.Div.1980). Further, although we consider the ALJ’s Initial decision as part of the record, it is TPAF that “is the primary factfinder” and it is TPAF’s decision that we review. Public Advocate Dep’t v. Public Utilities Bd., 189 N.J.Super. 491, 507 (App.Div.1983); see also Hiering v. Board of Trustees of Public Employees, 197 N.J.Super. 14, 19 (App.Div.1984).
Applying the appropriate standard of review, we conclude that there is no basis to disturb TPAF’s determination. We have found no statutory or regulatory authority to permit the reopening of a retirement plan once it becomes due and payable. A member is entitled to change an application for retirement at any time before his retirement allowance becomes due and payable; thereafter the retirement shall stand as approved by the board. See N.J.A.C. 17:8-6.2(a). A member’s retirement allowance becomes “due and payable” 30 days after the board’s approval of the application. NJ.A.C. 17:3-6.3(a). Petitioner’s final retirement selection of the maximum benefits was approved as of March 1, 1984 and thus became “due and payable” on April 1, 1984. Therefore, her ordinary disability retirement plan became fixed on that date. Implicit in TPAF’s determination is a respect for the finality of a retirement plan as. found in the regulatory scheme and a proper consideration of the essential need to protect the financial integrity of the pension system from unanticipated conversions at added cost to the fund. See Fiola v. N.J. Treas. Dept., 193 N.J.Super. 340 (App.Div.1984).
Notwithstanding the absence of authority in the statute or regulations to reopen, our Supreme Court in Duvin v. State, 76 N.J. 203 (1978), held that an administrative body has the inherent power, in the absence of legislative restriction, to reopen or modify orders previously entered. However, that power must be exercised reasonably and invoked only for good cause shown, and only where the applicant acted with reasonable diligence. Id. at 207 Duvin involved a public employees request to PERS to convert an early retirement allowance to an accidental disability retirement. The court remanded to PERS for a “good-cause” hearing as to the employee’s application. Id. at 208.
Applying Duvin to the facts before us, we are satisfied that petitioner failed to demonstrate “good cause.” Citing Fiola v. N.J. Treas. Dept., supra, 193 N.J.Super. 340, petitioner argues that TPAF’s failure to advise her of the availability of early retirement and that ordinary disability benefits would be off-set by compensation payments when her application for accidental disability benefits was denied constitutes “unfair dealing” and thus “good cause” under Duvin to reopen and convert to early retirement.
In our view, keeping in mind our narrowly circumscribed scope of review, there is no basis for petitioner’s claim of “unfair dealing.” The sole purpose of TPAF’s December 19, 1983 letter was to advise petitioner of the denial of her application for accidental disability benefits, and the granting of ordinary disability benefits. It focused entirely upon petitioner’s disability application made pursuant to N.J.S.A. 18A:66-39 and thus had no reason to address early retirement eligibility under N.J.S.A. 18A:66~87. Contrary to petitioner’s claim, TPAF had no “long-standing practice” of advising employees of their right to convert to early retirement when their accidental disability, claim is denied. TPAF’s policy is to offer members who file for a particular retirement plan a better benefit if the member qualifies. Here, the alternative plan paying the highest benefit to petitioner when her accidental benefit claim was denied was the ordinary disability plan.
There is ample evidence to support TPAF’s findings that petitioner knew at the time her accidental disability claim was denied that she knew of her entitlement to early retirement benefits, and further that ordinary disability benefits would be off-set by workers’ compensation payments. Petitioner had TPAF’s “benefit booklet,” which described eligibility for early retirement, before she applied for accidental benefits. She therefore knew, or should have known, of her eligibility for early retirement prior to the time her disability plan became fixed, but elected not to apply for those benefits.
Further, the booklet, her application for accidental disability benefits, and TPAF’s letter of February 7, 1984 advising petitioner of the ordinary disability options, all referred to the effect a workers’ compensation award could have on her disability retirement allowance. Thus, petitioner was placed squarely on notice that her election of a disability retirement program may be effected by the consequences of her workers’ compensation ease. Petitioner was represented by counsel both during her appeal from the denial of her accidental disability claim and in her workers’ compensation case. There is no question that, as of the date petitioner’s accidental disability claim was denied, the status of the law was that all public employee disability pensions, including teachers’ disability pensions, were subject to the workers’ compensation set-off, and that age and service pensions were not. See N.J.S.A. 18A:66-82.1; N.J.S.A. 84:15-43; Starkey v. Treasury Dept Pensions Div., supra, 183 N.J.Super. at 4-5. Both counsel could have advised petitioner that her ordinary disability retirement plan was subject to a workers’ compensation set-off as a matter of law. It was therefore not “unfair” for TPAF to assume that petitioner would know of the off-set without so advising her.
Moreover, while TPAF knew when it denied petitioner’s accidental disability claim that she had a pending workers’ compensation claim, it had no way to evaluate what compensation award, if any, would ultimately be entered. Petitioner and her counsel were clearly in the best position to predict the probable quantum of a set-off the compensation award would have on petitioner’s disability benefits. Thus, petitioner and not TPAF, was best able to choose the most beneficial retirement program after consideration of the potential consequence of a workers’ compensation set-off.
Our dissenting colleague, in asserting that TPAF’s findings are not supportable, focuses on segments of petitioner’s testimony before the ALJ which are essentially self-serving. What the dissent ignores is that we must review the “proofs as a whole” in the record before TPAF to determine whether the agency’s decision is supportable. Mayflower Securities v. Bureau of Securities, supra, 64 N.J. at 93. Although petitioner testified she did not know her ordinary disability benefits would be off-set by compensation payments, the benefits booklet, disability application and the February 7, 1984 letter from TPAF regarding the ordinary disability benefit options, all reminded her that the disability allowance could be subject to a reduction. TPAF could conclude from this evidence, as well as the fact that petitioner was represented by counsel in both her disability claim appeal and compensation case, that she knew her ordinary disability benefits were subject to reduction as a matter of law, despite her testimony to the contrary. Indeed, it may well be that petitioner and counsel were of the view at the time petitioner accepted the ordinary disability plan, that the compensation claim, not yet resolved, would not reduce the ordinary disability benefits below what petitioner would receive under early retirement, and thus chose the latter. The point is that the AU’s acceptance of petitioner’s testimony as being credible is not dispositive; so long as sufficient credible evidence on the record as a whole supports the agency’s factfinding, we must give deference to it.
As we have stated, the only issue before us is whether or not there was such “good cause shown” under Duvin, supra, 76 N.J. at 207, to reopen petitioner’s retirement plan; that is, whether TPAF acted “fairly” in not advising petitioner at the time her application for accidental disability was denied that she had an option to seek early retirement instead of ordinary disability benefits. The dissent’s conclusion that there was no fair dealing here is predicated solely on its “fact-finding” that petitioner did not know ordinary disability benefits would be off-set by compensation payments. By making such a finding, the dissent undercuts the agency’s independent fact-finding role and ignores our scope of review. We conclude that TPAF’s fact-finding and its implied determination that it did not deal unfairly with petitioner, are supportable on the record.
Fiola v. N.J. Treas. Dept., supra, 193 N.J.Super. 340, on which petitioner relies, is distinguishable. Fióla was a firefighter who resigned his membership in the Police and Firemens’ Retirement System. Upon his resignation, PFRS notified him that he was eligible to apply for the withdrawal of his contribution to the fund. While the notification also contained a list of various retirement possibilities, no application form was included with the notice other than that pertaining to the withdrawal of contributions. When Fióla applied approximately five years later for a deferred net allowance, PFRS denied the request because more than two years had elapsed after his last payment into the fund. See N.J.S.A. 43:16A-3(3). We reversed, noting that the denial was tantamount to a “[forfeiture of earned pension rights, drastic penalty which the New Jersey Supreme Court has become increasingly loath to permit[.]” Id. at 347-348. In dictum, we further noted that in sending only an application for withdrawal of contributions, PFRS dealt unfairly with Fióla since the notice “clearly intended to encourage exercise of the withdrawal option and conse quent termination of any further pension opportunity____” Id. at 351.
Here, there is no “consequent termination of any further pension opportunity____” Indeed, petitioner obtained the highest paying benefit available to her at the time her accidental disability application was denied. Further, TPAF’s dealings with petitioner were never calculated to mislead petitioner into forfeiting other options more beneficial to her. To the contrary, we are convinced that TPAF acted in good faith in processing petitioner’s disability application and that it had no obligation, in the circumstances here present, to advise petitioner of her eligibility for early retirement benefits. We therefore conclude that petitioner has not demonstrated the requisite “good cause” to reopen the ordinary disability plan and to convert to early retirement.
Affirmed.
The booklet containing the workers compensation set-off against all retirement plans, was published in 1973. In Starkey v. Treasury Dep’t, Pensions Div., 183 N.J.Super. 1, 6 (App.Div.), certif. den. 91 N.J. 190 (1982), we held that while a disability retirement plan was subject to a workers’ compensation set-off, a retirement plan based on age and service is not. See also State v. Garcia, 193 N.J.Super. 334 (App.Div.1984).