(1) Every taxpayer shall make a declaration of estimated tax for the taxable year, in such form as the department shall prescribe, if the amount payable as estimated tax can reasonably be expected to be more than $2,500. The term “estimated tax” shall mean the amount which the taxpayer estimates to be his or her tax under this code for the taxable year or, in the case of a taxable year of less than 12 months, an amount of tax determined in accordance with regulations prescribed by the department.
(2) A taxpayer may amend a declaration, under regulations prescribed by the department.