All retirement allowance payments due on or after October 1, 1975, to members of the Employees’ Retirement System of Alabama who retired prior to said date shall be redetermined as if the provisions of this division were in effect at the time they retired; provided, that any increase provided in the retirement allowance payment under this section for a member who retired under the provisions of any optional benefit elected pursuant to Article 1 of this chapter shall accrue only to the retired member, and no person designated to receive any payments after the death of a retired member under the provisions of any such optional benefit shall receive any increase in such payment under this section.