(1) To the extent not inconsistent with the provisions of this code or forms or regulations prescribed by the department, each taxpayer making a return under this code shall take into account the items of income, deduction, and exclusion on such return in the same manner and amounts as reflected in such taxpayer’s federal income tax return for the same taxable year.
(2) A final determination under the Internal Revenue Code adjusting any item or items of income, deduction, or exclusion for any taxable year shall be prima facie correct for purposes of this code to the extent such item or items enter into the determination of net income under this code.
(3) If there has been implementing legislation under s. 220.03(3), and to the extent required in regulations prescribed by the department, any taxpayer making a return under this code may be required to indicate the item or items of income, deduction, and exclusion which would enter into the determination of income if this code were amended to incorporate the Internal Revenue Code as amended and in effect for such taxable year. 
