(1) Any Fire Employee or Police Employee who was laid off in 1978 or 1980 and subsequently reinstated may elect at any time to purchase pension credit in the employee's current pension plan for the period of time the employee was laid off, provided that any employee making such election shall be required to pay such additional contributions which would have been paid by that employee had the employee been a member of the employee's current pension plan during the layoff period, plus interest on that amount calculated from the date the employee was reinstated. Interest shall be charged at the current rate determined by the Board's actuary to compensate the Pension Fund for lost interest, currently 9% compounded annually. The employee may pay such amount either in lump sum or by the installment plan under the terms set forth in Section 22-806 (Installment Payments) of this Ordinance.