Mo. Rev. Stat. § 86.193: Correction of errors in benefits, adjustments.

Should any change or error in records result in any member or beneficiary receiving from the retirement system more or less than he would have been entitled to receive had the records been correct, the board of trustees shall correct such error and, as far as practicable, shall adjust the payments in such a manner that the actuarial equivalent of the benefit to which such member or beneficiary was correctly entitled shall be paid.