72 Pa. Stat. § 1603-D.1
Notwithstanding any provision of law to the contrary, in the event that the rate of a payroll tax imposed by a city of the second class A, or a home rule municipality that was previously a city of the second class a, under section 123(d)(2) of the act of July 10, 1987 ( P.L. 246, No.47), known as the "Municipalities Financial Recovery Act," produces less than the revenues projected in the first full year after the imposition of a payroll tax, the city may, for a second year, adjust the rate to one that is sufficient to produce revenues equal to the revenues collected as a result of the mercantile or business privilege tax in the final year it was levied. The city may levy the payroll tax in any subsequent year at a rate not to exceed the adjusted rate authorized under this section.
72 P.S. § 1603-D.1