After the expiration of the ten days, council shall make the revision in the budget as deemed advisable. The budget must be as comprehensive and exact as the information available will permit. In addition to expenditures proposed for the current fiscal year, council may include as proposed expenditures a sum sufficient to pay any existing indebtedness and to pay the ordinary operating expenses for the subsequent year until the taxes of the subsequent year are received and may also include a sum to provide, in whole or in part, for any deferred maintenance, depreciation and replacements. Within the tax levy and debt limitations, council may also include, in whole or in part, expenditures for capital investments and purchases. Expenditures of a legislative character must be made, authorized or ratified by ordinance. Other expenditures allowed by law may be made or ratified by motion in council. The expenditures, whether by ordinance or motion, must then be considered as appropriations affecting the budget. A balance of revenues over expenditures may be expended in a subsequent year for a lawful purpose.