Other provisions of law to the contrary notwithstanding, any county or city not within a county who has elected or elects in the future to come under the provisions of sections 57.949 to 57.997 shall, after August 28, 2002, or on the date that such election is approved by the board of directors of the retirement system, whichever later occurs, be subject to the provisions of section 57.955.
§ 57.962, RSMo