74-49a21. Prior service credit for certain county engineers; basis for computation. Notwithstanding the provisions of K.S.A. 74-4913 to the contrary, any county engineer who first became a member of the Kansas public employees retirement system on June 1, 1965, having first been employed by another participating employer from September 16, 1947, until February 1, 1958, and having been employed by another participating employer from February 1, 1958, until June 1, 1964, shall receive prior service credit upon retirement for all services with all participating employers performed prior to June 1, 1964, whether such service was continuous or not. The prior service benefit shall be computed by using a prior service annual salary of eight thousand four hundred dollars ($8,400).