42 C.F.R. § 424.56
(b) Payment to the supplier. Payment to the supplier who submits the assigned claim is for whichever of the following amounts is less:
(d) Examples.
Example 1.An assigned bill of $300 on which partial payment of $100 has been made is submitted to the carrier. The carrier determines that $300 is the reasonable charge for the service furnished. Total payment due is 80 percent of $300 or $240. Of this amount, $200 (the difference between the $100 partial payment and the $300 reasonable charge) is paid to the supplier. The remaining $40 is paid to the beneficiary.
Example 2.An assigned bill of $325 on which partial payment of $275 has been made is submitted to the carrier. The carrier determines that $275 is the reasonable charge for the services. Total payment due is 80 percent of $275 or $220. The $220 is paid to the beneficiary, since any payment to the supplier, when added to the $275 partial payment would exceed the reasonable charge for the services furnished.
[53 FR 6641, Mar. 2, 1988; 53 FR 12945, Apr. 20, 1988]