(1) For purposes of the tax imposed by this code and the returns required to be filed, the taxable year of a taxpayer shall be the same as the taxable year of such taxpayer for federal income tax purposes.
(2) If the taxable year of a taxpayer is changed for federal income tax purposes, the taxable year of such taxpayer for purposes of this code shall be similarly changed.
(3) Notwithstanding the provisions of subsections (1) and (2), if the department terminates the taxable year of a taxpayer under the provisions of s. 220.719 relating to jeopardy assessments, the tax shall be computed for the period determined by such action. 
