42 CFR § 414.104 - PEN Items and Services.
(a) Payment rules. Payment for PEN items and services is made in a lump sum for nutrients and supplies that are purchased and on a monthly basis for equipment that is rented.
(b) Fee schedule amount. The fee schedule amount for payment for an item or service furnished in 2002 is the lesser of -
(i) The reasonable charge from 1995; or
(ii) The reasonable charge that would have been used in determining payment for 2002.