"Relation of Earnings to Insurance: If the total monthly amount of loss-of-time benefits promised for the same loss under all valid loss-of-time coverage upon the insured, whether payable on a weekly or monthly basis, exceeds the monthly earnings of the insured at the time disability commenced or the insured's average monthly earnings for the period of 2 years immediately preceding a disability for which claim is made, whichever is the greater, the insurer will be liable only for the proportionate amount of benefits under this policy that the amount of the monthly earnings or the average monthly earnings of the insured bears to the total amount of monthly benefits for the same loss under all coverage upon the insured at the time the disability commences and for the return of the part of the premiums paid during the 2 years that exceed the pro rata amount of the premiums for the benefits actually paid under this policy. However, this may not operate to reduce the total monthly amount of benefits payable under all coverage upon the insured below the sum of $200 or the sum of the monthly benefits specified in the coverages, whichever is the lesser, and may not operate to reduce benefits other than those payable for loss of time."
§ 33-22-227, MCA