Notwithstanding the provisions of Kan. Stat. Ann. §§ 74-4913 to the contrary, a county engineer of any county who first became a member of the Kansas public employees retirement system on February 1, 1963, while in the service with a participating employer, who had previously served as county engineer commencing in August of 1937 through February, 1944, entering the military service February 29, 1944, and serving in the Army of the United States until separated from service on December 6, 1945, and who returned to the position of county engineer with his previous employer in January of 1946 and served as county engineer for two (2) separate counties, consecutively, without a break in service until May 29, 1959, shall receive prior service credit under said retirement system for employment with all participating employers for service performed before January 1, 1962, whether such employment was continuous or not. The prior service benefit shall be computed by using the highest monthly salary the member received during the calendar year 1961 times twelve (12) as the prior service annual salary.