(1) Nothing contained in this chapter shall be construed to require a corporation to include an item of income, or to permit a corporation to deduct an expense item, more than once in computing Oregon taxable income.
(2) The changes to the corporate excise and income tax laws by chapter 162, Oregon Laws 1983, shall not be applied to preclude a corporation from taking into account a deduction or a loss to which it otherwise would be entitled.
(3) The changes to the corporate excise and income tax laws by chapter 162, Oregon Laws 1983, shall not be applied to preclude a corporation from including income which it otherwise would be required to include.