22 C.F.R. § 92.68
The fees for the taking of evidence by officers of the Foreign Service are as prescribed by the Tariff or Fees, Foreign Service of the United States of America (§ 22.1 of this chapter), under the caption "Services Relating to the Taking of Evidence," unless the service is performed for official use, which comes under the caption "Exemption for Federal Agencies and Corporations" of the same Tariff. See § 22.6 of this chapter concerning the requirement for advance deposit of estimated fees. When the party on whose behalf the evidence is sought or his local representative is not present to effect direct payment of such incidental costs as postage or travel of witnesses, the advance deposit required by the officer shall be in an amount estimated as sufficient to cover these in addition to the fees proper. The same rule shall apply to charges for interpreting or for the taking and transcribing of a stenographic record when performed commercially rather than by staff members at Tariff of Fee rates.
22 C.F.R. §92.68