Premiums for any policy period shall be paid into CompSource Oklahoma and adjusted according to the contract of insurance. If such adjusted premium is more than the premium paid at the beginning of the period, the employer shall pay the difference immediately upon notification of the amount of premium due. If such adjusted premium is less than the premium paid at the beginning of the period, the employer shall at the employer's option receive either refund of the difference or a credit of the amount thereof on the employer's account with CompSource Oklahoma.
Okla. Stat. tit. 85, § 391