A. Should any change or error in the records result in any member or beneficiary receiving from the retirement system more or less than he would have been entitled to receive had the records been correct, the board of trustees shall correct such error, and as far as practicable, shall adjust the payment in such a manner that the actuarial equivalent of the benefit to which such member or beneficiary was correctly entitled shall be paid.
B. The corrected benefit amount shall be paid prospectively. When considering corrections to the account of members for past erroneous benefit payments, the collection of overpayments or payment of underpayments may be waived if (1) it is deemed by the trustees to not be cost-effective for the system, in relation to the amount of the overpayment or underpayment, to attempt to locate the beneficiary or estate of such members and collect the overpayment or pay the underpayment or (2) if it is deemed by the trustees to cause an extreme hardship on the member or beneficiary.