A return with respect to the tax imposed by Section 2a.1 shall be made by every person for any taxable period for which such person is liable for such tax. Such return shall be made on such forms as the Department shall prescribe and shall contain the following information:
The returns prescribed by this Section shall be due and shall be filed with the Department not later than the 15th day of the third month following the close of the taxable period. The taxpayer making the return herein provided for shall, at the time of making such return, pay to the Department the remaining amount of tax herein imposed and due for the taxable period. Each taxpayer shall make estimated quarterly payments on the 15th day of the third, sixth, ninth and twelfth months of each taxable period. Such estimated payments shall be 25% of the tax liability for the immediately preceding taxable period or the tax liability that would have been imposed in the immediately preceding taxable period if this amendatory Act of 1979 had been in effect. All moneys received by the Department under Sections 2a.1 and 2a.2 shall be paid into the Personal Property Tax Replacement Fund in the State Treasury.
If any payment provided for in this Section exceeds the taxpayer's liabilities under this Act, as shown on an original return, the Department may authorize the taxpayer to credit such excess payment against liability subsequently to be remitted to the Department under this Act, in accordance with reasonable rules adopted by the Department.
35 ILCS 615/2a.2