If any change or error in the records of the fund or any participating employer or error in any calculation results in any person receiving from the fund more than that person would have been entitled to receive had the records been correct, the board shall correct the error and, as far as practicable, adjust the payment in such a manner that the actuarial equivalent of the benefit to which the person was entitled is paid or the board may offset the amount of the overpayment from the amount of future retirement benefit payments. However, if the person agrees to repay the fund for the cost of the error upon terms acceptable to the board, no actuarial adjustment to the person’s retirement benefit need be made.