(1) The actuary responsible for setting premium rates shall group similar policy forms, including forms no longer being marketed, in the pricing calculations. Such grouping shall rely on the judgment of the pricing actuary and be satisfactory to the commissioner. Among the factors which shall be considered are similar claims experience, types of benefits, reserves, margins for contingencies, expenses and profit, and equity between policyholders. Such grouping shall enhance statistical reliability and improve the likelihood of premium adequacy without introducing elements of discrimination in violation of RCW 48.18.480.

(2) The insureds under similar policy forms are grouped at the time of rate making in accord with RCW 48.18.480 because they are expected to have substantially like insuring, risk and exposure factors and expense elements. The morbidity and mortality experience of these insureds will, as a group, deteriorate over time. It is hereby defined to be an unfair and discriminatory practice, pursuant to RCW 48.01.030, 48.18.480 and 48.30.010, to withdraw a form from its assigned grouping by reason only of the deteriorating health of the people insured thereunder.

(3) One or more of the policy forms grouped for rate making purposes may, by random chance, experience significantly higher or more frequent claims than the other forms. It is hereby defined to be an unfair and discriminatory practice, pursuant to RCW 48.01.030, 48.18.480 and 48.30.010, to deviate from the assigned grouping of policy forms for pricing purposes at the time of requesting a rate increase unless the actuary can justify to the satisfaction of the commissioner that a different grouping is more equitable because of some previously unrecognized and nonrandom distinction between forms or between groups of insureds.

(4) Successive policy forms of similar benefits are sometimes introduced by the insurers for the purpose of keeping up with trends in hospital costs, new developments in medical practice, additional supplemental benefits offered by competitors, and other reasons. While this is commendable, policyholders who can not qualify for the new improved policies, or to whom the new benefits are not offered, are left insured and isolated as a high risk group under the prior form and soon become subject to massive rate increases. It is hereby defined to be an unfair and discriminatory practice, pursuant to RCW 48.01.030, 48.18.480 and 48.30.010, to fail to combine successive generic policy forms and to fail to combine policy forms of similar benefits covering generations of policyholders in the calculation of premium rates and loss ratios.