Okla. Admin. Code § 590:10-1-20
Actuarial cost for the purpose of withdrawing from the System pursuant to Section 910 of Title 74 of the Oklahoma Statutes shall be determined in accordance with the generally accepted actuarial principles and procedures using methodologies and assumptions which are consistent with those utilized in the actuarial valuation report for the most recent Fiscal Year ending June 30. The actuarial cost to withdraw from the System shall be calculated by the consulting actuary for the System. The employer requesting the withdrawal shall be responsible for paying any fees, costs and expenses for professional services associated with determining the actuarial cost to withdraw from the System. The employer shall also be responsible for any reasonable costs and expenses of the System to retrieve documents for the determination of the actuarial cost to withdraw from the System.
Okla. Admin. Code § 590:10-1-20