(1) In addition to the monthly retirement pension provided by section 31-30-1122, the board of a municipality, with the prior consent of the municipality's governing body, or the board of a fire protection district or county improvement district may pay a supplemental monthly retirement pension to a volunteer firefighter who is fifty years of age and who has been in active service more than twenty years if:(a) An actuarial review indicates a supplemental monthly pension payment is actuarially sound; and(b) Sixty-five percent of the total number of fire department members and retired fire department members give prior approval.(2) The supplemental monthly pension payment shall not exceed five percent of the monthly pension payment provided by section 31-30-1122 multiplied by the number of years of active service in excess of twenty years, up to a maximum of ten years; except that the total of the monthly retirement pension payment provided by section 31-30-1122 and the supplemental monthly pension payment shall not exceed an amount that is actuarially sound.L. 95: Entire part added, p. 1376, § 2, effective June 5. L. 98: (2) amended, p. 65, § 3, effective March 23.