(a) Under such rules and regulations as the Board of Control shall adopt, each person who was a teacher prior to October 1, 1940, and who under the provisions of this chapter makes up contributions plus eight percent compound interest on such contributions for the time said teacher taught as a nonmember and who becomes a member prior to October 1, 1974, shall file a detailed statement of all service as a teacher rendered by him prior to October 1, 1940, for which he claims credit. The Board of Control shall fix and determine by appropriate rules and regulations how much service in any year is equivalent to one year of service, but in no case shall it allow any credit for a period of absence without pay for more than one month's duration, nor shall more than one year of service be creditable for all service in one calendar year. Service rendered for a regular school year shall be equivalent to one year's service. Subject to the above restrictions and to such other rules and regulations as the Board of Control may adopt, the Board of Control shall verify, as soon as practicable after the filing of such statements of service, the service therein claimed. Upon verification of the statements of service, the Board of Control shall issue prior service certificates certifying to each member the length of service rendered prior to October 1, 1940, with which he is credited on the basis of his statement of service. Any prior service certificate heretofore issued not providing for the maximum prior service to which the member is entitled shall be revised to include such credit. So long as membership continues, a prior service certificate shall be final and conclusive for retirement purposes as to such service, provided, that any member may request the Board of Control to modify or correct his prior service certificate. When membership ceases, a prior service certificate shall become void. Should a teacher again become a member, he shall enter the system as a teacher not entitled to prior service credit. Creditable service at retirement on which the retirement allowance of a member shall be based shall consist of the membership service rendered by him since he last became a member and also, if he has a prior service certificate, which is in full force and effect, the amount of the service certified on his prior service certificate.

(b) Any teacher, or retired teacher, who became a member of the retirement system before July 1, 1973, and who prior to said date had been ineligible to receive credit for services rendered as a teacher prior to September 1, 1941, for reasons other than having taught as a nonmember shall be eligible under the rules and regulations adopted by the Board of Control in accordance with the provisions of this chapter to receive credit for all service as a teacher rendered by him prior to October 1, 1940; provided, that such person has never waived his claim on the funds of the retirement system by withdrawing his accumulated contributions to said fund; and provided, that said member has not been absent from service more than five years in any period of six consecutive years after becoming a member of the retirement system.

(c) Any teacher who was a member of the Teachers' Retirement System as of September 9, 1955 shall be eligible to receive credit for service rendered as a state employee on a full-time basis prior to October 1, 1945, under such rules and regulations as may be adopted by the Board of Control in accordance with the provisions of this chapter.

(d) Anything in this chapter to the contrary notwithstanding, any teacher who is now a member of the Teachers' Retirement System or who becomes a member of the Teachers' Retirement System at a future date, who had previously withdrawn his funds from either the Teachers' Retirement System or the Employees' Retirement System or whose account had been terminated due to a five year absence shall have restored to him all creditable service, provided, that said teacher completes two years of contributing membership service after he again becomes a member of the retirement system; and provided, that said teacher repays to the treasurer of the retirement system the amount previously returned to him including compounded interest of eight percent to the date of repayment, prior to the date of retirement of said member. Notwithstanding the foregoing provisions any member who elects to purchase credit for withdrawn service shall be eligible to purchase such credit only to the extent that such member does not have credit established with any other public retirement system for such period of service. Should any member have established part credit with another public retirement system for any period of withdrawn service, then such member shall only be eligible to purchase that portion of such withdrawn service for which such member does not otherwise have credit. In determining credit with other public retirement systems coverage under the federal Social Security program shall not be considered.

(e) Anything in this chapter to the contrary notwithstanding any teacher who has been retired from service and who is now receiving a service retirement allowance or a disability retirement allowance, pursuant to Section 16-25-14, who had five years or more of contributing membership service in the Teachers' Retirement System immediately prior to being retired and who had previously withdrawn his funds either from the Teachers' Retirement System or the Employees' Retirement System or whose account had been terminated due to five years' absence shall have restored to him all creditable service; provided, that said retired teacher pays to the treasurer of the retirement system within one year after October 1, 1982, the amount previously returned to him including compound interest of eight percent to the date of repayment.