(1) If a return is timely filed by the taxpayer but the tax is not paid, the commissioner shall make his assessment of tax due by mail or by personal delivery of the assessment to the taxpayer, which assessment shall constitute notice and demand for payment. The taxpayer shall be given a period of sixty (60) days from the date the commissioner mailed or hand delivered the notice in which to pay the tax due, including penalty and interest as provided in this section, and if the sum is not paid within the sixty-day period, the commissioner shall proceed to collect it under the provisions of Sections 27-13-29 through 27-13-41 of this chapter; provided that within the sixty-day period the taxpayer may appeal to the Board of Review as provided by law.

(2) If no return is made by a taxpayer required by this chapter to make a return, the commissioner shall determine the taxpayer’s liability from the best information available, which determination shall be prima facie correct for the purpose of this chapter, and the commissioner shall forthwith make an assessment of the tax so determined to be due by mail or by personal delivery of the assessment to the taxpayer, which assessment shall constitute notice and demand for payment. The taxpayer shall be given a period of sixty (60) days from the date the commissioner mailed or hand delivered the notice in which to pay the tax due, including penalty and interest as provided in this section, and if the sum is not paid within the sixty-day period, the commissioner shall proceed to collect it under the provisions of Sections 27-13-29 through 27-13-41 of this chapter; provided that within the sixty-day period the taxpayer may appeal to the Board of Review as provided by law.

(3)

(a) Except as otherwise provided in this subsection, interest at the rate of one percent (1%) per month on the total amount of the deficiency or delinquency of the tax from the due date of the return may be added or assessed in addition to the tax due as provided in subsections (1) and (2) of this section.

(b) For taxes assessed by the commissioner on or after January 1, 2015, the rate of any interest assessed under this section shall be:

(i) Nine-tenths of one percent (9/1 of 1%) per month for such taxes assessed on or after January 1, 2015, and before January 1, 2016;

(ii) Eight-tenths of one percent (8/1 of 1%) per month for such taxes assessed on or after January 1, 2016, and before January 1, 2017;

(iii) Seven-tenths of one percent (7/1 of 1%) per month for such taxes assessed on or after January 1, 2017, and before January 1, 2018;

(iv) Six-tenths of one percent (6/1 of 1%) per month for such taxes assessed on or after January 1, 2018, and before January 1, 2019; and

(v) One-half of one percent (½ of 1%) per month for such taxes assessed on or after January 1, 2019.

(4) In case of failure to file a return as required by this chapter, unless it can be shown that the failure is due to reasonable cause and not due to willful neglect, there may be added to the amount required to be shown as tax on the return a penalty of five percent (5%) of the total amount of the deficiency or delinquency of the tax if the failure is for not more than one (1) month, with an additional five percent (5%) for each additional month or fraction thereof during which the failure continues, not to exceed twenty-five percent (25%) in the aggregate.

(5) In case of failure to pay the amount shown as tax on any return specified in subsections (1) and (2) of this section on or before the date prescribed for payment of the tax, determined with regard to any extension of time for payment, unless it is shown that the failure is due to reasonable cause and not due to willful neglect, there may be added to the amount shown as tax on the return one-half of one percent (½ of 1%) of the total amount of the deficiency or delinquency of the tax if the failure is for not more than one (1) month, with an additional one-half of one percent (½ of 1%) for each additional month or fraction thereof during which the failure continues, not to exceed twenty-five percent (25%) in the aggregate.