(1) No paid firefighter, retiring under the provisions of chapter 14, title 72, Idaho Code, shall receive more than one hundred percent (100%) of the firefighter’s average compensation for the three (3) consecutive years which produce the greatest aggregate compensation, which said monthly sum shall vary annually according to the determination of the "cost of living adjustment" as set forth in section 72-1471, Idaho Code.
(2)  As the amount, terms and conditions of benefits under this chapter may be revised from time to time, the application of such revisions shall be prospective only and not retrospective or retroactive unless otherwise provided by law.