(a) This section and Sections 854.406, 854.407, 854.408, 854.409, and 854.410, providing for an occupational disability benefits program, apply to municipalities having a participation date in the retirement system after August 31, 1987. The governing body of any municipality having an earlier effective date of participation may by ordinance adopt the provisions of this section and Sections 854.406, 854.407, 854.408, 854.409, and 854.410 in lieu of the disability program provided for under Subchapter D.
(b) A governing body may not adopt an ordinance under this section unless the actuary first determines, on the basis of mortality and other tables adopted by the board of trustees, that all obligations of the municipality to the benefit accumulation fund, including obligations proposed under the ordinance, can be funded by the municipality within its maximum contribution rate and within its amortization period.