(b) Special rule for part-year residents. In the case of a part-year resident, the ordinary income portion of a lump sum distribution wholly or partly derived from or connected with New York sources shall be the sum of:
(1) The ordinary income portion of a lump sum distribution for the period of residence, computed as if the taxable year for federal income tax purposes were limited to the period of residence.
(2) The ordinary income portion of a lump sum distribution for the period of nonresidence, determined in accordance with subsection (a) of this section, computed as if the taxable year for federal income tax purposes were limited to the period of nonresidence.