411.4 SERVICE CREDITABLE. 1. Service for fewer than six months of a year is not creditable as service. Service of six months or more of a year is equivalent to one year of service, but in no case shall more than one year of service be creditable for all service in one calendar year, nor shall the system allow credit as service for any period of more than one month duration during which the member was absent without pay. 2. The system shall credit as service for a member of the system a previous period of service only under any of the following circumstances: a. The member had withdrawn the member's accumulated contributions, as defined in section 411.21, for the previous period of service. b. The member returned to service after an absence of service of a period of less than four years from the last day of the prior period of service. c. The member returned to service after an absence of service of a period of four or more years from the last day of the prior period of service and the member had sufficient service as of the last day of the prior period of service to have been entitled to a retirement allowance on that date under section 411.6, subsection 1, paragraph "b".

411.4 SERVICE CREDITABLE. 1. Service for fewer than six months of a year is not creditable as service. Service of six months or more of a year is equivalent to one year of service, but in no case shall more than one year of service be creditable for all service in one calendar year, nor shall the system allow credit as service for any period of more than one month duration during which the member was absent without pay. 2. The system shall credit as service for a member of the system a previous period of service only under any of the following circumstances: a. The member had withdrawn the member's accumulated contributions, as defined in section 411.21, for the previous period of service. b. The member returned to service after an absence of service of a period of less than four years from the last day of the prior period of service. c. The member returned to service after an absence of service of a period of four or more years from the last day of the prior period of service and the member had sufficient service as of the last day of the prior period of service to have been entitled to a retirement allowance on that date under section 411.6, subsection 1, paragraph "b".