Subject to § 58-18-20, every blanket health insurance policy shall contain a provision that all benefits payable under the policy other than benefits for loss of time will be payable immediately upon receipt of due written proof of such loss, and that, subject to due proof of loss, all accrued benefits payable under the policy for loss of time will be paid not later than at the expiration of each period of thirty days during the continuance of the period for which the insurer is liable, and that any balance remaining unpaid at the termination of such period will be paid immediately upon receipt of such proof.
SDCL 58-18-25