(2) In determining the sources of a nonresident partner’s income, no effect shall be given to a provision in the partnership agreement which:

(a) Characterizes payments to the partner as being for services or for the use of capital, or allocated to the partner, as income or gain from sources outside this state, a greater proportion of the partner’s distributive share of partnership income or gain than the ratio of partnership income or gain from sources outside this state to partnership income or gain from all sources, except as authorized in subsection (4) of this section; or

(b) Allocates to the partner a greater proportion of a partnership item of loss or deduction connected with sources in this state than the proportionate share of the partner, for federal income tax purposes, of partnership loss or deduction generally, except as authorized in subsection (4) of this section.

(3) Any modification to federal taxable income described in this chapter that relates to an item of partnership income, gain, loss or deduction (or item thereof) shall be made in accordance with the partner’s distributive share, for federal income tax purposes of the item to which the modification relates, but limited to the portion of such item derived from or connected with sources in this state.

(4) The department may, on application, authorize the use of such other methods of determining a nonresident partner’s portion of partnership items derived from or connected with sources in this state, and the modifications related thereto, as may be appropriate and equitable, on such terms and conditions as it may require.

(5) A nonresident partner’s distributive share of items of income, gain, loss or deduction (or item thereof) shall be determined under ORS 314.714 (2). The character of partnership items for a nonresident partner shall be determined under ORS 314.714 (1). [1989 c.625 §32 (enacted in lieu of 316.352)]