(b) Upon becoming fifty-two (52) years of age, a fund member receiving a Class 1 impairment benefit or Class 2 impairment benefit under section 13.5(h)(2) of this chapter is entitled to receive a monthly supplemental benefit determined in STEP THREE of the following formula: STEP ONE: Determine the greater of:
(A) the monthly retirement benefit payable to a fund member with twenty (20) years of service; or(B) the monthly retirement benefit payable to a fund member with the total years of service (including both active service and the period, not to exceed twenty (20) years, during which the member received disability benefits) and salary, as of the year the fund member becomes fifty-two (52) years of age, that the fund member would have earned if the fund member had remained in active service until becoming fifty-two (52) years of age.STEP TWO: Subtract from the amount determined under STEP ONE the amount of any monthly benefit determined under section 13.5 of this chapter that the fund member is entitled to receive for the remainder of the fund member's life.
STEP THREE: Determine the greater of the following:
(A) The remainder determined under STEP TWO.