FF is a heavy Tank counter and its Pop is fine
Jagpanzer is medium tank counter and should have its pop reduced.
They are literally in the same class. Both 60 range TDs, just jagdpanzer gets defensive vet while FF vet is offensive.
JP is the best nondoc counter to British heavy tanks axis have. It eats Churchill's for breakfast better than panther or StuG. And it also beats FF head on in 1vs1 due to superior DPS.
So there's not much logic OKW having cheaper vehicle popcap when their repairs need one Sturm at most (thanks to mech truck) while Brits you're looking at multiple RE squads