The commission shall from time to time certify to the board of education the amount of its expenses, which amount shall be a legal charge upon the school district payable to the commission, and may be raised by the issuance of notes by the board of education, but the amounts so certified, if remaining unpaid, and the amounts of any notes so issued shall be included by the board of education, without any authorization by the legal voters of the school district, in the next succeeding amount certified to the county board of taxation as the amount to be raised by taxation for the purposes of the school district.