If the premiums are determined according to age of the insured debtor or by age brackets, appropriate adjustments in the rate and premium may be made according to age if such adjustments are actuarially consistent with the foregoing rates when applied regardless of actual age at issue and if such adjustments produce an aggregate premium not substantially greater than that produced by the foregoing rates, and such rates and actuarially consistent computations are filed with and approved by the commissioner of insurance.
28 Tex. Admin. Code § 3.5306