38 C.F.R. § 14.810
(b)
(1) When a request is granted under § 14.808 to permit VA personnel to testify in whole or in part as to expert, opinion or policy matters, the requester shall pay to the government a fee calculated to reimburse the cost of providing the witness. The fee shall include:
(f) Fees shall be paid as follows:
(g) A waiver of any fees in connection with the testimony of an expert witness may be granted by the appropriate VA official at the official's discretion provided that the waiver is in the interest of the United States. Fee waivers shall not be routinely granted, nor shall they be granted under circumstances which might create the appearance that the VA or the United States favors one party or a position advocated by a party to the legal proceeding.
(Authority: 38 U.S.C. 501 (a) and (b); 5 U.S.C. 301)