Notwithstanding the provisions of Kan. Stat. Ann. §§ 74-4913 to the contrary, any employee of a participating employer with an entry date of January 1, 1967, who became a member of the Kansas public employees retirement system on October 1, 1966, who was employed by such participating employer on January 4, 1955, until January 5, 1965, and who was employed by another participating employer from October 1, 1965, until December 31, 1969, shall upon retirement be entitled to receive prior service credit for employment with the participating employer for the period January 4, 1955, until January 5, 1965. The prior service benefit shall be computed by using a prior service annual salary of six thousand eight hundred thirty-four dollars and seventeen cents ($6,834.17).