N.Y. Comp. Codes R. & Regs. Tit. 20 §§ 4-1.7
(Tax Law, sections 211(3), 1083, 1087)
The business apportionment factor (BAF), as determined under section 210-A and this Subchapter, upon which the taxpayer's report (or any additional assessment) was based, must not be changed during the additional period of limitation allowed in the case of non-filing of a report of a Federal change, correction or renegotiation of tax, or a computation or re-computation of tax; or in the case of a report of a Federal change, correction or renegotiation of tax, or a computation or re-computation of tax; or in the case of a deficiency based on a net operating loss carryback or a net capital loss carryback. Both the commissioner and the taxpayer are precluded from adjusting the BAF in such cases. Under the same circumstances, a petition for the redetermination of a deficiency or a notice of deficiency does not open the BAF.
N.Y. Comp. Codes R. & Regs. Tit. 20 §§ 4-1.7