(1) The actuarial cost to purchase creditable service by members who first became members on or after July 1, 1989, will vary by the member's compensation, age and years of service at the time they apply or are eligible to purchase the additional service.

(a) The total compensation reported to the teachers' retirement system for the most recent fiscal year will be used to determine the actuarial cost.

(b) The members age at the time they make application to purchase service will be determined in compliance with ARM 2.44.525.

(c) The years of service will be determined by the total number of years of creditable service the member is eligible to receive on the date they apply or are eligible to purchase service under this rule.

(2) Service will be credited to the member's account at the time they have completed payment in full. If the member terminates payments or advises the TRS that they will not make any further payments, the service purchased will be credited on a prorated basis.