Former inspection mechanic, friendly neighborhood popo here,
I'm a bit slow on this one...
PennDOT unofficially removed tint as a pass/fail from the inspection process, years ago, although the table is still in the manual.
Every modern vehicle produced already has a~30% tint (70% light transmittance) from the factory. Rear windows on vans, SUVs, etc are exempt.
As far as we (the popo) is concerned, PA VC (title 75), SS4524(e), Windshield obstructions and wipers, covers it.
BUT, current case law trumps the written law and that is, any tint (non-factory) that obscures the identity of any operator or passenger, is illegal.
So, you could be legal during the day, but illegal at night, by that standard.
You can be stopped in PA for just about any, non factory, modifications to a vehicle, being cited for the same is a whole other story.
Bottom line is, won't fail inspection and most cops don't care.