Mo. Rev. Stat. § 87.300
The deductions provided for herein shall be made notwithstanding that the minimum compensation provided by law for any member shall be reduced thereby. Every member shall be deemed to consent to the deductions made and provided for herein, and shall receipt for his full salary or compensation, and payment of salary or compensation less the deduction shall be a full and complete discharge and acquittance of all claims and demands whatsoever for services rendered during the period covered by the payment except as to benefits provided by sections 87.120 to 87.370. The chief of the fire department shall certify to the board of trustees on each and every payroll or in such other manner as the board of trustees shall prescribe the amount deducted, and such amounts shall be paid into the members' savings fund and shall be credited to the individual account of the member from whose compensation the deduction was made.
§ 87.300, RSMo