Notwithstanding the provisions of subsection (2)(b) of Kan. Stat. Ann. §§ 74-4913 and subsection (17) of Kan. Stat. Ann. § 74-4902, and any amendments to such statutes, to the contrary, an individual who was born November 24, 1910, and who became a member of the Kansas public employees retirement system on February 1, 1969, and who was first employed by the entry date employer on February 1, 1968, and who continued in employment with such participating employer until such member’s retirement under the Kansas public employees retirement system on January 1, 1982, shall have such member’s salary for the 13 months immediately preceding retirement included in calculation of final average salary for the purpose of determining monthly retirement benefits. Any increase in monthly retirement benefits as a result of this recalculation shall commence on the first day of the month coinciding with or following the effective date of this act.