Notwithstanding the provisions of Kan. Stat. Ann. §§ 74-4915 to the contrary, an employee of a participating employer who became a member of the retirement system on July 1, 1970, who had previously been employed as an elected official having taken office on January 8, 1957, who served in such office until January 14, 1969, whose date of birth is July 3, 1913, and who is serving in the same office as when first becoming a member of the system, shall upon retirement have all retirement benefits calculated using final average salary for all credited service.