An Inmate in the custody of the Department of Corrections, not serving a probationary term as a result of a deferment or suspension of a sentence and not on parole, who has served, in actual custody, the shorter of five (5) years of the term or terms of imprisonment, or one-third (1/3) of the total term or terms of imprisonment, shall be eligible for commutation consideration of a sentence except for a conviction of impeachment.
Okla. Admin. Code § 515:15-3-1