(1) Notwithstanding any other provision of this chapter, an active or inactive member who is vested may purchase up to forty-eight (48) months of membership service.
(2) The cost of purchases under this section shall be the full actuarial costs of the service as determined by the board. The board may provide for payment options, including periodic payments, but no service shall be credited until payment has been made in full. The member shall be solely responsible for the costs of such purchased service, except that an employer may participate in the costs at its option.
(3) In no event shall any member be allowed to purchase in the aggregate more than forty-eight (48) months of membership service under this section.