Mo. Rev. Stat. § 87.305
87.305 Refunds of contributions, when.
87.305. Refunds of contributions, when. — The board of trustees is authorized at its discretion to make refunds or grant additional benefits for such parts of contributions as were made prior to the adoption of the eight percent rate for all members which were in excess of the compulsory contributions required of each member.
(L. 1943 p. 708 § 8, A.L. 1959 S.B. 314 § 86.577, A.L. 1977 H.B. 308)