(a) The retirement allowance of any beneficiary under the Tennessee teachers' retirement system or the Tennessee state retirement system shall be increased as of July 1, 1972, as follows:

(1) The retirement allowance which would otherwise be payable, without regard to the election of any optional modification, shall be increased by ten percent (10%) of the amount of retirement allowance which would otherwise be payable before application of any flat minimum benefit formula or any post retirement increase and without regard to the election of any optional modification, but the total retirement allowance shall not exceed seventy-five percent (75%) of the beneficiary's average final compensation.

(2) The retirement allowance recomputed under subdivision (a)(1) shall not be less than sixty-four dollars and eight cents ($64.08) for a retired former Class A member, multiplied by the number of years of the member's creditable service, nor less than seventy-two dollars ($72.00) for a retired former Class B member, multiplied by the number of years of the member's creditable service.

(3) In no event shall the increase in the retirement allowance of any beneficiary under this section be less than twelve dollars ($12.00) multiplied by the number of years of creditable service.

(b) Notwithstanding the foregoing, any member of the Tennessee state retirement system who retired as a Class C member of that system or under the special benefit provisions of that system applicable to firefighters and police officers or wildlife officers shall not be entitled to an increase in the member's retirement allowance under this section.