(a) Rating factors used to underwrite qualifying health benefit plans must produce premium rates for identical groups that:
(1) differ only by the amounts attributable to health benefit plan design; and
(2) do not reflect differences because of the nature of the groups assumed to select a particular health benefit plan.
(b) A health benefit plan issuer shall treat each qualifying health benefit plan that is issued or renewed in a calendar month as having the same rating period.

(c) A health benefit plan issuer may use only age and gender as case characteristics, as defined by Section 1501.201(2), in setting premium rates for a qualifying health benefit plan.
(d) The commissioner by rule may establish additional rating criteria and requirements for qualifying health benefit plans if the commissioner determines that the criteria and requirements are necessary to achieve the purposes of this chapter.