(FERC) under the Natural Gas Act (US Code, tit 15, § 717
et seq.), and resells the gas at retail to customers in western New York, northwestern Pennsylvania and northeastern Ohio. Supply Corp. commingled natural gas and coke oven gas containing a lower Btu content, which mixture was sold to Distribution Corp. for resale to its customers in New York State. Because Supply Corp.’s interstate wholesale rates are established by FERC on a volumetric basis (i.e., dollars/per million cubic feet), while Distribution Corp.’s New York retail rates are established by the PSC on a heat content basis (i.e., dollars/per million Btu), an anomaly or incongruity in the rate structure resulted. The PSC, during petitioner’s 1975 rate increase case, found that New York State customers were paying for higher quality (1,000 Btu) gas but were receiving a lower quality product (992.3 Btu content) because it contained a mixture of coke oven gas, and ordered a “Btu adjustment” effective November 1, 1976. FERC thereupon ordered a Btu adjustment in Supply Corp.’s wholesale rates effective November 1,1977, but did not adjust the wholesale rates for any prior period, specifically the one year between November 1, 1976 and November 1, 1977. As a result of the adjustments, Distribution Corp. received a $13.6 million refund from Supply Corp. in December, 1979, and proposed that the PSC permit it to retain $3.8 million of such refund as compensation for a shortfall in revenue experienced during the aforesaid one-year period between 1976-1977 and not covered retroactively by the FERC Btu adjustment. Respondent PSC, in a July 15,1980 order, partially rejected Distribution Corp.’s application, by directing it to flow through to its New York State customers $1,694,066 of the refund while permitting it to retain $2,119,904. Upon petitioner’s application for reconsideration, and for a hearing pursuant to subdivision 2 of section 113 of the Public Service Law, respondent PSC, in a September 25, 1980 order, adhered to its previous determination and further held that petitioner was not entitled to such a hearing. Thereupon, petitioner commenced this CPLR article 78 proceeding seeking to annul and vacate for lack of subject matter jurisdiction so much of respondent’s November 16,1976 and February 1, 1977 orders as imposed the retail Btu price adjustment. Petitioner’s principal argument was that the 1976 and 1977 orders were not fully implemented and effectuated until the July 15 and September 25, 1980 orders, and, alternatively, that the 1980 orders, made without a hearing, were violative of subdivision 2 of section 113 of the Public Service Law. Special Term dismissed the petition as time barred insofar as it sought review of the November 16, 1976 and February 1, 1977 orders, and granted that portion of the petition annulling the July 15 and September 25,1980 orders because they were made without a hearing. Petitioner has appealed only from that part of the judgment which dismissed as time barred its challenge to the November 16, 1976 and February 1, 1977 orders. CPLR 217 establishes a four-month Statute of Limitations applicable to article 78 review of administrative determinations. This time limitation commences when the determination becomes final and binding and when its impact can be accurately assessed and petitioner knows whether it is aggrieved
(Matter of Jewish Mem. Hosp. v Whalen, 47 NY2d 331 , 343; see, also,
Matter of Martin v Ronan, 44 NY2d 374 ;
Mundy v Nassau County Civ. Serv. Comm., 44 NY2d 352 ). Accordingly, the dispositive date upon which the four-month time period for commencement of proceedings to review the challenged PSC orders is the date when the orders became final and binding upon petitioner and upon which petitioner knew it was aggrieved. It is clear that the orders became final and binding upon issuance. Petitioner' argues that it was impossible to assess the impact of the Btu adjustment until the subsequent determinations in 1980 ordered the flow-through of refunds received by petitioner from Supply Corp. pursuant to the FERC determination,