42 CFR § 417.804
Cost apportionment
June 11, 2020
(a) The HCPP follows the cost apportionment principles specified in §§417.552 through 417.566, except for provisions on provider costs and provisions on departmental apportionment.
(b) The HCPP may use a method for reporting costs that is approved by CMS. CMS bases its approval on a finding that the method—
(1) Results in an accurate and equitable allocation of allowable costs; and
(2) Is justifiable from an administrative and cost efficiency standpoint.