20 C.F.R. § 702.413
All fees charged by medical care providers for persons covered by this Act shall be limited to such charges for the same or similar care (including supplies) as prevails in the community in which the medical care provider is located and shall not exceed the customary charges of the medical care provider for the same or similar services. Where a dispute arises concerning the amount of a medical bill, the Director shall determine the prevailing community rate using the OWCP Medical Fee Schedule (as described in 20 CFR 10.805 through 10.810) to the extent appropriate, and where not appropriate, may use other state or federal fee schedules. The opinion of the Director that a charge by a medical care provider disputed under the provisions of section 702.414 exceeds the charge which prevails in the community in which said medical care provider is located shall constitute sufficient evidence to warrant further proceedings pursuant to section 702.414 and to permit the Director to direct the claimant to select another medical provider for care to the claimant.
20 C.F.R. §702.413