In Department of Environmental Protection v. City of Philadelphia, 692 A.2d 598 (Pa. Cmwlth. 1997), the City questioned the Department's decisions on the City's Act 339 application for the years 1989 through 1992, when the Department imposed a 1.5% limitation on interest expense eligible for subsidy under Act 339. The Court agreed that the Department's 1.5% limitation was improper. For the years appealed, 1989-1992, this court determined that the actual cost, rather than the 1.5% limitation imposed by the Department, should be used in calculating the amount of subsidy owed. The Court further stated that the right to challenge the 1.5% rate for pre-1989 decisions was waived.