Returns made on the basis of the calendar year shall be made and filed, and the tax imposed by this chapter shall be paid, on or before April 20 following the close of the calendar year. Returns made on the basis of a fiscal year shall be made and filed, and in such case the tax imposed by this chapter shall be paid, on or before the twentieth day of the fourth month following the close of the fiscal year.

A taxpayer may elect to pay the tax in four equal installments, in which case the first installment shall be paid on the date prescribed for the payment of the tax, the second installment shall be paid on the twentieth day of the second month, the third installment on the twentieth day of the fifth month, and the fourth installment on the twentieth day of the eighth month after such date. Notwithstanding the preceding, if the total tax liability under this chapter for the taxable year exceeds $100,000, the taxes so levied shall be payable in twelve equal installments, in which case the first installment shall be paid on or before the tenth day of the first month following the close of the taxable year, and the remaining installments shall be paid on or before the tenth day of each calendar month after such date. If any installment is not paid on or before the date fixed for its payment, the department, at its election, may cause the balance of the tax unpaid to become payable upon not less than ten days’ notice and demand, and this amount shall be paid upon the date so fixed in the notice and demand from the department. The department shall prescribe the forms in which returns shall be made.

The provisions of chapter 235 regarding the limitation period for assessment and refunds shall run from the filing of the return for the taxable year, or the due date prescribed for the filing of the return, whichever is later.