OPTIONAL METHOD OF REPORTING: PERCENTAGE OF SALES.

(a) A seller who is a retail grocer, a seller who operates a separate grocery department having separate records that are separately auditable, or any other seller whose taxable receipts from the sale of taxable items are less than 10 percent of the total receipts of the seller may determine the total taxable receipts of the grocer, separate grocery department, or other seller by:

(1) adding the amount of all invoices for merchandise sold to the seller during the preceding calendar or fiscal year to obtain the total sum of merchandise purchased;

(2) adding the amount of all invoices for exempt merchandise sold to the seller during the preceding calendar or fiscal year to obtain the total sum of exempt merchandise purchased;

(3) dividing the sum obtained under Subdivision (2) of this subsection by the sum obtained under Subdivision (1) of this subsection to obtain a percentage relationship;

(4) multiplying the percentage obtained under Subdivision (3) of this subsection times the total sales by the seller for the reporting period to obtain the total nontaxable sales of the seller; and

(5) subtracting the total nontaxable sales of the seller obtained under Subdivision (4) of this subsection from the total sales by the seller during the reporting period to obtain the total taxable receipts of the seller from sales of tangible personal property.

(b) A seller determining taxable receipts as provided by Subsection (a) of this section shall add to the total taxable receipts the sales prices of all purchases made by the seller that are subject to the use tax and on which the use tax has not been paid.

(c) If the comptroller audits a seller who qualifies for and uses the method of reporting allowed by this section and determines that the actual tax liability of the seller computed on the actual taxable receipts of the seller differs from the amount reported and paid under this section, the comptroller shall collect the difference due to the state, if any, or refund or credit the seller with the difference that is an overpayment to the state, if any.

(d) The comptroller may not assess a penalty or interest against a seller because of an underpayment of the actual tax due disclosed by an audit under Subsection (c) of this section unless the audit discloses wilful evasion of the tax or fraud. The state may not pay interest on an overpayment disclosed by an audit under Subsection (c) of this section.

(e) Under procedures adopted by and with the consent of the comptroller, a seller eligible to determine its total taxable receipts under this section may add to the amount provided by Subdivision (2) of Subsection (a) of this section an additional amount that represents that portion of the amount of all invoices for merchandise sold to the seller during the preceding calendar or fiscal year that was not considered exempt merchandise for purposes of Subdivision (1) of Subsection (a) of this section but that became exempt under Section 151.3141 of this code when sold.