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 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 ). (6) Rule of construction Nothing in this subsection shall be construed to inhibit the authority of an Indian tribe to enter into or maintain a compact or contract under the Indian Self-Determination and Education Assistance Act ( 25 U.S.C. 5304 et seq.). (7) Effective dates (A) In general Except as provided in subparagraph (B), this subsection shall take effect on October 1, 2019. (B) Regulations, applications, and reports Effective on the date of the enactment of the Restoring Accountability in the Indian Health Service Act of 2017 , the Secretary may— (i) prescribe regulations for carrying out this subsection