A. Coordination of benefit requirements adopted by health insurance issuers shall, at a minimum, adhere to the following requirements:
(1) No plan shall contain a provision that its benefits are "always excess" or "always secondary" except in accordance with rules adopted by the commissioner pursuant to this Subpart.
(2) A coordination of benefit provision may not be used that permits a plan to reduce its benefits on the basis of any of the following:
(a) That another plan exists and the covered person did not enroll in the plan.
(b) That a person is or could have been covered under another plan, except with respect to Part B of Medicare.
(c) That a person has elected an option under another plan providing a lower level of benefits than another option that could have been elected.
B. The commissioner shall be authorized to adopt such reasonable regulations as necessary for determining the order of benefit payments when a person is covered by two or more plans of health insurance coverage.