Section 18-52 Miscalculation of benefits, payment of interest on underpayment or overpayment.

W henever a miscalculation of benefits due a retiree or beneficiary which results in an underpayment is discovered, interest on the underpayment shall be paid to the retiree or beneficiary at a rate equal to the annual investment rate of return on the police retirement fund as determined by the annual actuarial statement for each year of the underpayment. Whenever an overpayment is discovered, the retiree or beneficiary shall repay the amount erroneously paid in excess of the benefit due him plus interest for the time of overpayment equal to the annual investment rate of return on the fund as determined by the annual actuarial statement for each year of overpayment. If the amount of overpayment and interest thereon is greater than one monthly benefit payment, repayment shall be made to the fund in the same manner as provided for reimbursement by the retiree of lump sum worker's compensation benefits in section 18-4 3 of this Article.