Purpose of act.

The purpose of this act is to provide a supplement to the monthly retirement benefits being paid to, or with respect to, retired members under the retirement systems specified in s. 112.352(5) and any permanently and totally disabled retired member who became thus disabled in the line of duty and while performing the duties incident to his or her employment, such supplement to be approximately equal to the excess of the increase in social security benefits that the retired member would have received had he or she been covered for maximum benefits under the Social Security Act at age 65 or at date of retirement, whichever is later, over the amount of increase he or she has previously received or is entitled to receive by virtue of coverage under the Social Security Act.