(1) Unless otherwise specifically provided, the interest rate assessed on delinquent payments of any taxes or special assessments owing to the State of Nebraska shall be assessed at a rate of fourteen percent per annum through December 31, 1992, and at the per annum rate determined pursuant to subsection (2) of this section after such date.

(2) Commencing January 1, 1993, the interest rate assessed pursuant to subsection (1) of this section shall be redetermined every other year. The rate shall be determined by the Tax Commissioner and shall be equal to the average short-term borrowing rate for the federal government during July of the previous year rounded to the nearest whole percentage point plus three percentage points. If the new rate does not increase or decrease the old rate by at least two percentage points, the old rate shall continue in effect.

(3)(a) The rate determined pursuant to subsection (2) of this section shall apply for the period from its effective date through the date of payment or up to the effective date of the succeeding new rate, whichever is earlier.

(b) Interest on taxes or special assessments shall be calculated using the different rates which are effective over the period of delinquency.

(c) For any taxes or special assessments that were delinquent and unpaid on or before December 31, 1992, the interest rate shall be fourteen percent per annum through December 31, 1992.

(4) For any credits or refunds of taxes or special assessments on which interest is to be determined at the rate specified in this section, the calculation of interest shall use the same rates for the same periods that are used for interest on delinquent payments.

(5) For refunds applied for on or after May 1, 1993, for any taxes that were overpaid as of December 31, 1992, the interest rate shall be seven percent per annum from the date of overpayment through December 31, 1992.