Those persons eligible under subsections (a) or (b) of Section 45-45-235 and 45-45-235.02 who may elect to become a supernumerary sheriff shall be entitled to receive a cost-of-living increase as the remuneration of the office of sheriff increases from which the supernumerary sheriff elected to vacate. The cost-of-living increase allowed the supernumerary sheriff shall be equal to the percentage of any cost-of-living increase granted to the sheriff in office.