In determining assessment ceilings, the commissioner shall apply the final state equalization rate used for the local assessing jurisdiction on the assessment roll for the year immediately preceding the year in which the assessment ceiling is being established, except that (1) if a special equalization rate was established for such assessment roll, such rate shall be applied, and (2) in the case of a special assessing unit as defined in section eighteen hundred one of this chapter, the equalization rate to be applied shall be the applicable class equalization rate used on such assessment roll.
N.Y. Real Prop. Tax. Law § 499-NNNN