(A) The sum of the amount shown as the tax by the taxpayer on the return of the taxpayer, if a return was made by the taxpayer and an amount was shown as the tax by the taxpayer thereon, plus the amounts previously assessed (or collected without assessment) as a deficiency, over

(B) The amount of refunds (as defined in ORS 314.415) made.

(b) There shall then be ascertained the increase or decrease in tax previously determined which results solely from the correct treatment of the item in the computation of gross income, taxable income, and other matters under ORS 316.317 or ORS chapter 317 or 318. A similar computation shall be made for any other taxable year affected, or treated as affected, by an Oregon net loss for prior years (as provided by ORS 317.476 or 317.478 and section 45b, chapter 293, Oregon Laws 1987), by a net operating loss deduction (as defined in the federal Internal Revenue Code) or by a capital loss carryback or carryover (as defined in the federal Internal Revenue Code) determined with reference to the taxable year with respect to which the error was made. The amount so ascertained (together with any amounts wrongfully collected as additions to the tax or interest, as a result of such error) for each taxable year shall be the amount of the adjustment for that taxable year.

(2) The adjustment authorized in ORS 314.115 (1) shall be made by assessing and collecting, or refunding or crediting, the amount thereof in the same manner as if it were a deficiency determined by the Department of Revenue with respect to the taxpayer as to whom the error was made or an overpayment claimed by such taxpayer, as the case may be, for the taxable year or years with respect to which an amount is ascertained under subsection (1) of this section and as if on the date of the determination one year remained before the expiration of the periods of limitation upon assessment or filing claim for refund for such taxable year or years. If, as a result of a determination described in ORS 314.105 (1)(d), an adjustment has been made by the assessment and collection of a deficiency of the refund or credit of an overpayment, and subsequently such determination is altered or revoked, the amount of the adjustment ascertained under subsection (1) of this section shall be redetermined on the basis of such alteration or revocation and any overpayment or deficiency resulting from such redetermination shall be refunded or credited, or assessed and collected, as the case may be, as an adjustment under this part. In the case of an adjustment resulting from an increase or decrease in a net operating loss or net capital loss which is carried back to the year of adjustment, interest shall not be collected or paid for any period prior to the close of the taxable year in which the net operating loss or net capital loss arises.

(3) The amount to be assessed and collected in the same manner as a deficiency, or to be refunded or credited in the same manner as an overpayment, under ORS 314.105 to 314.135, shall not be diminished by any credit or setoff based upon any item other than the one which was the subject of the adjustment. The amount of the adjustment under ORS 314.105 to 314.135, if paid, shall not be recovered by a claim or suit for refund or suit for erroneous refund based upon any item other than the one which was the subject of the adjustment. [1971 c.248 §5; 1983 c.162 §51; 1987 c.293 §52a]