(a) Before the 16th day of each month, each participating municipality shall pay or cause to be paid to the retirement system at the system’s office expense contributions in accordance with § 855.404, current service contributions in accordance with § 855.405, and prior service contributions in accordance with § 855.406.
(b) Unless otherwise provided for and paid by a municipality, a municipality shall pay its contributions to the retirement system from:
(1) the fund from which earnings are paid to members; or
(2) the general fund of the municipality.