A metropolitan government, as defined in §7-1-101, is hereby authorized by ordinance or resolution of its governing body to direct or permit its trustee, as a convenience to its taxpayers, to prepare and send to each owner of taxable property a bill for the amount of taxes due on the property. Where the property is located within the urban services district, the governing body may authorize the tax for the urban services district and the tax for the general services district to be consolidated into one (1) tax bill, computed on the combined tax rate of both of the taxing districts; provided, that the tax rate for each of such districts shall be shown plainly on the face of the consolidated tax bill. In any case where the taxpayer pays as much as one half (½) of the total amount of the combined tax bill not later than October 31 of the year for which the taxes are due, and the remaining one half (½) not later than February 28 of the following year, no interest or penalty shall be charged, notwithstanding any state law, charter or ordinance of the metropolitan government to the contrary.