(1) A member of the PERS, game wardens' and peace officers' retirement system, or highway patrol officers' retirement system may request to purchase out-of-state or federal public service by writing a letter to the board. The letter must contain the following information certified by the member's former employer:

(a) dates of employment, full- or part-time employment status, weekly or monthly hours of employment if part-time, date and amount of refund, and current membership status; or

(b) if the member was employed before the employer adopted a public retirement system, the information in (1) (a) and, if applicable, the name of the public retirement system and the date the employer adopted it.

(2) The board will calculate the actuarial cost of granting the service based upon the member's preceding 12 month's salary.