Please tell me how I am inaccurate. Perhaps I am misunderstanding your question.
Here is the information directly from the Parole Board's website So as I originally stated at 1/3 of his sentence, the minimum amount of time is 4 years. At 85% it is 24 years.
When is an offender eligible for parole consideration?
Although there is no formal application that must be completed for parole consideration, the Parole Board has the authority to consider offenders outside of the regular docketing process; however, this is rare.
Under current law an offender is eligible for parole after one-third of sentence has been served if the offense was for a non-violent crime. Offenders convicted of certain violent offenses, which occurred after March 2000 or later must serve 85% of their sentence prior to becoming eligible for parole consideration. Those offenses are such things as Murder I, Robbery I, Rape I, Burglary I, Arson I, Child Abuse, Child Beating and Child Pornography. See Title 21 O. S. §13.1
All other violent offenses are eligible for parole consideration at one-third of the sentence. The procedures of the Parole Board docket offenders for their initial parole consideration two months before their actual eligibility date to allow for processing to the Governor's Office.