Sec. 7. (a) After each fiscal year, the actuary shall report the status of the reserve account for persons receiving benefits from the fund. The report must contain a statement of the reserves in the account and the accrued liability for these persons.
(b) Taking into consideration the actuary's report, the board shall after June 30, 1985, charge the costs of postretirement benefit increases against any difference between the reserves in the account and the accrued liability. However, the board may withhold from the difference, as a contingency reserve, an amount less than or equal to two percent (2%) of the reserve. If the amount of the difference is insufficient to meet the costs of the postretirement benefit increases, the excess shall be charged against each employer's account in the retirement allowance account on a prorata basis.