661—402.200 (97A) Computation of average final compensation. Computation of the average final compensation shall be made using the earnable compensation of the member during the three years of the member’s service as a member of the department during which the member received the highest amount of compensation. Overtime compensation, if any, and periods without pay shall not be considered in this computation.
Exception:  If a member retires before attaining three years of service, the average final compensation shall be the total of the earnable compensation from the date the member was sworn into service divided by the number of months of service and multiplied by 12.