(a) Each dealer, on or before the twentieth day of each month, shall transmit returns to the commissioner showing the gross sales and purchases arising from all sales and purchases taxable under this article during the preceding calendar month. The commissioner may provide by regulation for quarterly or annual returns or, upon application, may permit a dealer to file a return on a quarterly or annual basis if deemed advisable by the commissioner. The returns required by this subsection shall be made upon forms prescribed, prepared, and furnished by the commissioner.

(b) As used in this subsection, the term "estimated tax liability" means a dealer's tax liability, adjusted to account for any subsequent change in the state sales and use tax rate, based on his average monthly payments for the last fiscal year. If the estimated tax liability of a dealer for any taxable period exceeds $2,500.00, the dealer shall file a return and remit to the commissioner not less than 50 percent of the estimated tax liability for the taxable period on or before the twentieth day of the period. The amount of the payment of the estimated tax liability shall be credited against the amount to be due on the return required under subsection (a) of this Code section. This subsection shall not apply to any dealer unless during the previous fiscal year the dealer's monthly payments exceeded $2,500.00 per month for three consecutive months or more. No local sales taxes shall be included in determining any estimated tax liability.

(c) Gross proceeds from rentals or leases of tangible personal property shall be reported and the tax shall be paid with respect to the gross proceeds in accordance with the rules and regulations prescribed by the commissioner.

(d)(1) The commissioner, in his discretion, may grant extensions, upon written application, to the end of the calendar month in which any tax return is due under this Code section.

(2) No extension granted pursuant to paragraph (1) of this subsection shall be valid unless granted in writing and only for a period of not more than 12 consecutive months.

(3) Upon the grant of any extension authorized by this subsection, the taxpayer shall remit to the commissioner on or before the date the tax would otherwise become due without the grant of the extension an amount which, when added to the amount previously remitted for the period pursuant to subsection (b) of this Code section, equals not less than 100 percent of the dealer's payment for the corresponding period of the preceding tax year.

(4) No interest or penalty shall be charged, assessed, or collected by reason of the granting of an extension pursuant to this subsection.

(5) This subsection shall apply to all extensions granted pursuant to this subsection on or after July 1, 1980, and to all extensions granted pursuant to this subsection and in effect on July 1, 1980.