official reception and representation expenses in an amount not to exceed $1,500, to remain available until expended: Provided , That notwithstanding 31 U.S.C. 3302 and section 5 of the Flood Control Act of 1944, up to $6,500,000 collected by the Southeastern Power Administration from the sale of power and related services shall be credited to this account as discretionary offsetting collections, to remain available until expended for the sole purpose of funding the annual expenses of the Southeastern Power Administration: Provided further , That the sum herein appropriated for annual expenses shall be reduced as collections are received during the fiscal year so as to result in a final fiscal year 2019 appropriation estimated at not more than $0: Provided further , That notwithstanding 31 U.S.C. 3302 , up to $55,360,000 collected by the Southeastern Power Administration pursuant to the Flood Control Act of 1944 to recover purchase power and wheeling expenses shall be credited to this account as offsetting collections, to remain available until expended for the sole purpose of making purchase power and wheeling expenditures: Provided further , That for purposes of this appropriation, annual expenses means expenditures that are generally recovered in the same year that they are incurred (excluding purchase power and wheeling expenses). Operation and maintenance, southwestern power administration For expenses necessary for operation and maintenance of power transmission facilities and for marketing electric power and energy, for construction and acquisition of transmission lines, substations and appurtenant facilities, and for administrative expenses, including official reception and representation expenses in an amount not to exceed $1,500 in carrying out section 5 of the Flood Control Act of 1944 ( 16 U.S.C. 825s ), as applied to the Southwestern Power Administration, $45,802,000, to remain available until expended: Provided , That notwithstanding 31 U.S.C. 3302 and section 5 of the Flood Control Act of 1944 (