(a) Notwithstanding any other provisions to the contrary, in any year in which there is a change in the formula for retirement allowances, any beneficiary of the Tennessee teachers' retirement system, the Tennessee state retirement system, or of Group 1 of the Tennessee consolidated retirement system shall, on July 1 of such year, have such beneficiary's benefits recomputed according to the then existing provisions of the Tennessee consolidated retirement system. The recomputed benefit shall be compared to the benefit at the time of retirement or as of the date of the most recent recomputation, whichever date is later, and if the recomputed benefit is larger, the difference shall be added to the then current benefit. The increase provided by this section shall be in addition to any increases permitted under § 8-36-701.

(b)

(1) For the purposes of recomputing benefits as provided in subsection (a), a change in the formula shall be defined as follows:

(A) The conditions of eligibility for retirement as provided in § 8-36-201;

(B) The service retirement allowance formula as provided in §§ 8-36-206 — 8-36-208, and the service retirement allowance for Class B members as provided in the superseded Tennessee teachers' retirement system or the superseded Tennessee state employees' retirement system;

(C) The minimum service retirement allowance as provided in § 8-36-209;

(D) The early service retirement allowance as provided in part 3 of this chapter;

(E) The disability retirement allowance as provided in part 5 of this chapter; and

(F) The definition of “average final compensation” as defined in § 8-34-101.

(2) Notwithstanding the formula changes listed in subdivision (b)(1)(A)-(F), a change in the formula shall not include for recomputation purposes any increase in state retirement benefits for active employees to offset a reduction in the benefits paid by social security which is necessary to maintain the approximate level of benefits for active employees.

(c) The benefit of a state judge who retires prior to September 1, 1990, as a Group 3 member shall be recalculated under Acts 1986, ch. 554.

(d) The governing body of a political subdivision may, at its option, by resolution authorize and accept the liability for its active and retired employees to receive any increases due to a change in the benefit formula. It is the intent of this enactment that should the governing body elect to authorize its employees to receive increases, resulting from a change in formula, such authorization and acceptance of liability therefor shall include both active and retired employees.