Section 141.663 - Declaration of estimated tax not withheld; computation; payment; installments(1) A taxpayer's annual return for the preceding year may be used as the basis for computing a declaration of estimated tax for the current year, or the taxpayer may use the same figures used for estimating federal income tax adjusted to exclude any income or deductions not taxable or permissible under this ordinance.(2) Except as otherwise provided, the estimated tax may be paid in full with the declaration or in 4 equal installments on or before the last day of the fourth, sixth, ninth, and thirteenth months after the beginning of the taxpayer's taxable year. For tax years after the 1996 tax year and for which a city has entered into an agreement pursuant to section 9 of chapter 1, the estimated tax shall be paid in 4 equal installments on or before the fifteenth day of the fourth, sixth, ninth, and thirteenth months after the beginning of the taxpayer's taxable year.(3) An amended declaration may be filed when making a quarterly payment, and the unpaid balance shown due shall be paid in equal installments over the remaining payment dates.1964, Act 284, Imd. Eff. 6/12/1964 ;--Am. 1996, Act 478, Eff. 1/1/1997 .