Order unanimously affirmed without costs. Memorandum: Supreme Court properly denied plaintiff’s motion for summary judgment. Plaintiff commenced this action seeking a declaration concerning the computation of rent and other payments due under a commercial lease signed in 1975 and amended twice. We agree with plaintiff that the lease unambiguously provides for a rental increase of 2% based upon an advance in the Consumer Price Index (CPI) of 10%, not 10 points, as defendant contends. Defendant, however, submitted proof in evidentiary form raising an issue of fact whether the parties’ assignors intended to eliminate the CPI-based increases when they amended the lease in 1985 and 1989. Where, as here, resolution of an ambiguous contractual provision "turns on questions of credibility and the choice between reasonable inferences to be drawn therefrom, determination of the intent of the parties is a question of fact for the trier of fact” (Show Car Speed Shop v United States Fid. & Guar. Co., 192 AD2d 1063, 1065). Contrary to plaintiff’s contention, extrinsic evidence may be submitted to determine the parties’ intent in this case (see, State of New York v Home Indem. Co., 66 NY2d 669, 671). Defendant also raised an issue of fact regarding the proper computation of maintenance costs under the lease. (Appeal *971from Order of Supreme Court, Onondaga County, Tormey, J.— Summary Judgment.) Present — Pine, J. P., Fallon, Callahan, Doerr and Davis, JJ.