220.44 Adjustments.—If it appears to the director that any agreement, understanding, or arrangement exists between any taxpayers, or between any taxpayer and any other person, which causes any taxpayer’s net income subject to tax to be reflected improperly or inaccurately, the director may adjust any item or items of income, deduction, or exclusion, or any factor taken into account in apportioning income to this state, to the extent necessary clearly to reflect the net income of such taxpayer.