Okla. Admin. Code § 365:10-11-1
The purpose of this subchapter is to adopt the Model Group Coordination of Benefits Regulation, as promulgated by the National Association of Insurance Commissioners. This subchapter is intended to establish uniformity in the permissive use of over insurance provisions and to avoid claim delays and misunderstandings that could otherwise result from the use of inconsistent or incompatible provisions amount Plans. It is contrary to the public policy of this state for a Plan to declare its coverage to be "excess" to all others, or always "secondary", or to reduce its benefits because of the existence of duplicate coverage in a manner other than as permitted by this regulation; or to reduce its benefits because a person covered by the Plan is eligible for any other coverage. It is requested that courts give effect to this public policy when they consider the interrelation of Plans with order of benefit determination rules which comply with this subchapter and Plans with order of benefit determination rules which differ from those set forth in this subchapter.
Okla. Admin. Code § 365:10-11-1