The purchase price for each year of out-of-state service defined in OAC 715:10-5-21 shall be based on the actuarial cost as defined in OAC 715:10-5-4. All requests for billings to make payment for such service must be made while an active contributing member of TRS, or within sixty (60) days of termination of employment in the public schools of Oklahoma, but must be completed 90 days prior to the effective date of retirement. No person may request a billing to initiate the purchase out-of-state service credit after the date of death of the member.
Okla. Admin. Code § 715:10-5-26