(b) Limitations.

(1) The credit under this section shall not exceed the percentage of the tax otherwise due under this article determined by dividing the portion of the taxpayer's New York income subject to taxation by such other jurisdiction by the total amount of the taxpayer's New York income.

(2) The credit under this section shall not reduce the tax otherwise due under this article to an amount less than would have been due if the income subject to taxation by such other jurisdiction were excluded from the taxpayer's New York income.

(3) In the case of a taxpayer who elects to claim the foreign tax credit for federal income tax purposes, the credit under this section for income tax imposed by a province of Canada shall be allowed for that portion of the provincial tax not claimed for federal purposes for the taxable year or a preceding taxable year, provided however, to the extent the provincial tax is claimed for federal purposes for a succeeding taxable year, the credit under this section must be added back in such succeeding taxable year. The provincial tax shall be deemed to be claimed last for federal income tax purposes and for purposes of this subsection.

(c) Definition. For purposes of this section New York income means:

(1) the New York adjusted gross income of an individual, or

(2) the amount of the income of an estate or trust, determined as if the estate or trust were an individual computing his New York adjusted gross income under section six hundred twelve.

(d) S corporation shareholders. In the case of a shareholder of an S corporation, the term "income tax" in subsection (a) of this section shall not include any such tax imposed upon or payable by the corporation, but shall include any such tax with respect to the income of the corporation imposed upon or payable by the shareholder, without regard to whether an election independent of the federal S election was required to effect such imposition upon the shareholder.