1. 1. The board of trustees shall fix and determine by proper rules and regulations how much service in any year is equivalent to one year of creditable service, but in no case shall more than one year of service be creditable for all service in one calendar year, nor shall the board of trustees allow credit as service for any period of more than one pay period's duration, as shown on the salary and wage schedules of the employer, during all of which the member was absent without pay unless such member pays the employee contributions, including contributions by the employer in lieu of employee contributions, for such period as permitted by the board of trustees in accordance with the provisions of section 169.315.
2. 2. Under the rules and regulations that the board of trustees adopts, each member who was an employee on and prior to the date the retirement system becomes operative and who becomes a member within one year of such date shall file a detailed statement of all service as an employee for which such person claims credit rendered by such person prior to that date.
3. 3. Subject to the above restrictions and to the other rules and regulations that the board of trustees adopts, the board of trustees shall verify the service claims as soon as practicable, after the filing of the statements of service.
4. 4. Upon verification of the statements of service, the board of trustees shall issue prior service certificates, certifying to each member the length of prior service with which the member is credited on the basis of the member's statement of service. So long as the holder of a certificate continues to be a member, a prior service certificate shall be final and conclusive for retirement purposes as to such service; provided, however, that any member may, within one year from the date of issuance or modification of the certificate, request the board of trustees to modify or correct the person's prior service certificate. When any employee ceases to be a member, the person's prior service certificate becomes void, and if the person again becomes a member the person shall enter the retirement system as a member not entitled to prior service credit, except as provided in section 169.313.

(L. 1982 H.B. 1522 § 169.311 subsecs. 1 to 4, A.L. 1989 S.B. 146, A.L. 1994 S.B. 575, A.L. 1995 S.B. 378)