Section 211.075 - Payment of tax; returns; filing requirements; estimated tax declarations(1) The tax on oil production shall be due and payable on or before the 25th day of the month following the month production occurred. The tax on gas production and the tax on sulfur production shall be due and payable on or before the 25th day of the second month following the end of each calendar quarter.(2) Each producer shall file a return prescribed by the department listing the kind and quality of taxable products, the source and county of production, and the location of all oil or gas wells from which taxable products were produced. The return shall be filed on or before the last day prescribed for payment of the tax and shall be signed and verified under oath by the producer or the producer's authorized representative.(a) The return shall include a statement of the tax due under this part and such other information as the department may reasonably require.(b) A return shall be filed even though no tax is due. Any tax, penalty, or interest due shall be remitted with the return.(3)(a) Each person subject to the tax under s. 211.025 or s. 211.026 shall file, on a form prescribed by the department, a declaration of estimated tax on or before the 25th day of the month following the month production occurred and shall remit to the department an amount equal to 90 percent of the estimated tax.(b) The declaration may be amended under rules prescribed by the department, and the installment due shall be increased or decreased to reflect the change in estimated tax occasioned by the amendment.(c) The department may provide for credit of any overpayment of amounts due under this part which the department determines to have been made against the installment required under this subsection.(d) Any estimated tax paid for a month shall be deemed assessed upon the last date for payment of the tax under subsection (1).(4) If any due date prescribed by this section falls on a Saturday, Sunday, or state or federal holiday, the last date prescribed for filing or payment shall be the next day which is not a Saturday, Sunday, or holiday. The date of receipt by the department, or the postmark date if mailed, shall determine the timeliness of payment or filing.(5) The department may grant an extension of time for payment, or filing of a return, upon written request submitted on or before the due date.