(1) (a) Subject to subsection (1)(b) and 19-6-805, a member may, at any time before retirement, file a written application with the board to purchase 1 year of additional service credit for each 5 years of membership service that the member has in the retirement system.
(b) A member must have at least the following years of membership service to apply to purchase additional service credit under this section:
(i) for a member hired before July 1, 2013, 5 years; and
(ii) for a member hired on or after July 1, 2013, 10 years.
(2) To purchase service credit under this section, a member shall pay the actuarial cost of the service credit, based on the system's most recent actuarial valuation as determined by the board.
(3) Service credit purchased under this section is not membership service and may not be used to qualify a member for retirement or in the calculation of an actuarial reduction in benefits for a member who is not eligible for service retirement.