(a) Any active and contributing member of the Teachers' Retirement System may claim and purchase service credit in the system for any prior service described and limited as follows:
(1) Not more than one year for time spent on medical leave approved by the state or local employer.
(2) Not more than 10 years for full-time employment with the Alabama Legislature.
(3) Not more than four years for full-time employment with a subsidiary affiliate organization of an employer which has continually participated in the system since its inception.
(b) The purchase of any prior service credit under subsection (a) may occur at any time prior to the member's date of retirement. The certification of prior service claimed under this section shall conform to applicable administrative rules and procedures of the Teachers' Retirement System. Members shall receive credit for the prior service when they remit to the system the contributions required by subsection (c). No member shall receive credit for any service that the member is already credited with in the system or any other public retirement plan, with the exception of the federal Social Security program.
(c) Any member who is eligible to purchase service credit pursuant to subsection (a) shall pay to the Secretary-Treasurer of the system for the claimed service, the full actuarially determined cost for each year of claimed service as determined by the system's actuary.