Okla. Stat. tit. 70, § 70-17-116.8: Service credit - Computation of purchase price

A. The Board of Trustees shall adopt rules for computation of

the purchase price for service credit. These rules shall base the

purchase price for each year purchased on the actuarial cost of the

incremental projected benefits to be purchased. The purchase price

shall represent the present value of the incremental projected

benefits discounted according to the member's age at the time of

purchase. Incremental projected benefits shall be the difference

between the projected benefit said member would receive without

purchasing the service credit and the projected benefit after

purchase of the service credit computed as of the earliest age at

which the member would be able to retire. Said computation shall

assume an unreduced benefit and be computed using interest and

mortality assumptions consistent with the actuarial assumptions

adopted by the Board of Trustees for purposes of preparing the

annual actuarial evaluation.

B. In the event that the member is unable to pay the purchase

price provided for in this section by the due date, the Board of

Trustees shall permit the members to amortize the purchase price

over a period not to exceed sixty (60) months. Said payments shall

be made by payroll deductions unless the Board of Trustees permits

an alternate payment source. The amortization shall include

interest in an amount not to exceed the actuarially assumed interest

rate adopted by the Board of Trustees for investment earnings each

year. Any member who ceases to make payment, terminates, retires or

dies before completing the payments provided for in this section

shall receive prorated service credit for only those payments made,

unless the unpaid balance is paid by said member, his or her estate

or successor in interest within six (6) months after said member's

death, termination of employment or retirement, provided no

retirement benefits shall be payable until the unpaid balance is

paid, unless said member or beneficiary affirmatively waives the

additional six-month period in which to pay the unpaid balance. The

Board of Trustees shall promulgate such rules as are necessary to

implement the provisions of this subsection.