under clause (i) relating to health professional volunteers to the same extent and in the same manner as that subsection applies to the estimate under that subsection relating to officers, governing board members, employees, and contractors of entities described in subsection (g)(4). (C) Transfers Not later than December 31 of each fiscal year, the Secretary shall transfer from the fund under subsection (k)(2) to the appropriate accounts in the Treasury an amount equal to the estimate made under subparagraph (B) for the calendar year beginning in that fiscal year, subject to the extent of amounts in the fund. (5) Definition of service unit (A) In general In this subsection, the term Service unit has the meaning given the term in section 4 of the Indian Health Care Improvement Act ( 25 U.S.C. 1603 ). (B) Inclusion In this subsection, the term Service unit includes an urban Indian organization with which the Indian Health Service has entered into a contract with, or to which the Indian Health Service has made a grant, under title V of the Indian Health Care Improvement Act ( 25 U.S.C. 1651 et seq. ). (6) Effect Nothing in this subsection— (A) negatively impacts the right of an Indian tribe or Tribal organization to enter into a compact or contract under the Indian Self-Determination and Education Assistance Act ( 25 U.S.C. 5304 et seq. )