Notwithstanding the provisions of subsection (2) of Kan. Stat. Ann. §§ 74-4917 and 74-4932 and subsection (4) of Kan. Stat. Ann. §§ 74-4963 to the contrary, if an individual who was born October 7, 1929, and who became a member of the Kansas police and firemen’s retirement system on November 1, 1979, has credited service under the Kansas public employees’ retirement system, any retirement benefits to which such individual would have been entitled under the Kansas public employees retirement system shall become vested whenever the total credited service under both systems equal ten (10) years and any retirement benefits to which such individual shall be entitled to under the Kansas police and firemen’s retirement system shall become vested whenever the total credited service under both systems equal twenty (20) years. Upon such individual’s retirement, each such retirement system shall be liable for payment of retirement benefits under such system in the proportion that the years of such individual’s service under such system bears to such individual’s total years of service under both such systems. For the purpose of determining and computing retirement benefits and death and disability benefits computed upon the basis of “credited service” of such individual, the term “credited service,” as used in Kan. Stat. Ann. § 74-4951 et seq., and amendments thereto, shall mean and include only “participating service” under the Kansas police and firemen’s retirement system, except that service credited under the Kansas public employees retirement system to such individual shall be considered and included (a) in determining whether the death or disability of such individual was “service connected” under the provisions of subsection (10) of Kan. Stat. Ann. § 74-4952 and (b) for the purpose of determining the eligibility of such individual for non-service connected death and disability benefits under the provisions of subsection (2) of Kan. Stat. Ann. §§ 74-4959 and subsection (2) of Kan. Stat. Ann. § 74-4960.