Subject to RCW 44.04.260, all expenses incurred by the committee, including salaries and expenses of employees, shall be paid upon voucher forms as provided by the administrator and signed by the chair or vice chair of the committee and attested by the secretary of said committee, and the authority of said chair and secretary to sign vouchers shall continue until their successors are selected after each ensuing session of the legislature. Vouchers may be drawn on funds appropriated by law for the committee: PROVIDED, That the senate and the house may authorize the committee to draw on funds appropriated by the legislature for legislative expenses.