In Bast v. Rossoff, 91 NY2d 723 [1998] the Court held that the CSSA is applicable to joint custody cases. In its holding, the Court continued that in shared custody cases, child support must first be calculated using the three-step formula set forth in the CSSA and there is no exception carved out in CSSA for shared custody cases. Significantly, the Appellate Court in Bass recognized, inter alia, that "There will certainly be shared custody cases where the statutory formula yields a result that is just and ap-propriate, notwithstanding the additional time spent with the child . . . Of course, there will also be shared custody cases where the statutory formula yields a result that is unjust or inappropriate. In those cases, however, the court can resort to the paragraph (f)' factors and order payment of an amount that is just and appropriate" (Bast at 729). Indeed, the court noted, "while it reduces certain costs for the custodial parent, shared custody actually in-creases the total cost of supporting a child by necessitating duplication of certain household costs in each parent's home" (Id at730). While the Court of Appeals explicitly rejected use of a "proportional offset" formula in shared custody cases, its ruling simply directed courts to calculate child support in accordance with the CSSA. The Court held that "In most instances, the court can determine the custodial parent for purposes of child support by identifying which parent has physical custody of the child for a majority of the time." (See Bast, 91 NY2d at 728.) The Court in Bast found further that "even though each parent has a custodial period in a shared custodial arrangement, for purposes of child support, the court can still identify the primary custodial parent." (Id. at 729.)