those excess amounts shall be available in future fiscal years only to the extent provided in advance in appropriations Acts: Provided further , That the sum herein appropriated from the general fund shall be reduced (1) as such fees are received during fiscal year 2019, net of amounts necessary to pay refunds due depositors, (estimated at $360,000,000) and (2) to the extent that any remaining general fund appropriations can be derived from amounts deposited in the Fund in previous fiscal years that are not otherwise appropriated, so as to result in a final fiscal year 2019 appropriation from the general fund estimated at $0. Salaries and expenses, foreign claims settlement commission For expenses necessary to carry out the activities of the Foreign Claims Settlement Commission, including services as authorized by section 3109 of title 5, United States Code, $2,409,000. Fees and expenses of witnesses For fees and expenses of witnesses, for expenses of contracts for the procurement and supervision of expert witnesses, for private counsel expenses, including advances, and for expenses of foreign counsel, $270,000,000, to remain available until expended, of which not to exceed $16,000,000 is for construction of buildings for protected witness safesites