(1) Where a budget has been passed the Municipality shall not incur any expenditure under any of the heads of the budget, other than a head providing for the refund of taxes in excess of the amount passed under that head, without making provision for such excess by the variation or alteration of the budget.
(2) Where any expenditure under any head providing for the refund of taxed is incurred in excess of the amount passed under that head, provision shall be made without delay for such expenditure by the variation or alteration of the budget.