(c) Require at least once a year the examination of the reasonableness of the percentage or percentages established in subdivision (a) of this subsection and determine the difference between the amount of sales and use taxes paid and the estimated actual tax liability.
(3) The Tax Commissioner shall adjust the percentage or percentages established in subdivision (2)(a) of this section for future periods as necessary to result in substantially all of the tax liability being paid each year.
(4) If the difference between the amount of sales and use taxes paid and the estimated actual tax liability is within the agreed-upon limits established in subdivision (2)(b) of this section, the percentages or amounts will be considered to have been reasonable for the preceding period, the tax liability shall be considered satisfied for such period, no additional tax payments shall be required for such period, and no refunds shall be allowed for such period. If such difference is not within the agreed-upon limits established in subdivision (2)(b) of this section, the difference shall be remitted to the state or refunded. Interest at the rate specified in section 45-104.01 , as such rate may from time to time be adjusted by the Legislature, shall be due on the underpayment or refund from the date of the last payment for the period until the date the amount is paid or refunded.