; and (3) to the extent available, domestically-sourced fuels shall be the preferred source for furnished energy for such Medical Center. (b) Subsection (a) shall not apply if the Secretary of Defense certifies to the congressional defense committees that a waiver of such subsection is necessary to protect the national security interests of the United States. 8128. The Secretary of Defense may obligate and expend funds made available under this or any other Act for procurement or for research, development, test and evaluation for the F–35 Joint Strike Fighter to modify up to six F–35 aircraft, including up to two F–35 aircraft of each variant, to a test configuration: Provided , That the Secretary of Defense shall, with the concurrence of the Secretary of the Air Force and the Secretary of the Navy, notify the congressional defense committees not fewer than 30 days prior to obligating and expending funds under this section. 8129. Amounts appropriated for Defense Health Program in this Act and hereafter may be obligated to make death gratuity payments, as authorized in subchapter II of chapter 75 of title 10, United States Code, if no appropriation for Military Personnel is available for obligation for such payments: Provided, That such obligations may subsequently be recorded against appropriations available for Military Personnel . 8130. None of the funds appropriated or otherwise made available by this or any other Act may be obligated or expended by the Department of Defense to migrate data and applications to the proposed Joint Enterprise Defense Infrastructure or the Defense Enterprise Office Solutions cloud computing services until a period of 90 days has elapsed following the date on which the Secretary of Defense submits to the congressional defense committees— (1) a proposed plan to establish a budget accounting system that provides transparency across the Department, including all military Services and Defense Agencies, for funds requested and expended for all cloud computing services procured by the