The Churchill's pop could be knocked down to 16 from 19 but the Firefly is much better than the SU-85
Churchill at 16 would be way too low. It is actually the KV-1 that need to have the pop increased. It currently has the same as the OKW PzIV while being superior.
The SU-85 has the best gun in the game especial when vetted so imo it superior to FF. And again it the SU-85 that need to have its pop increased to 16.
The pop of both KV-1 and SU-85 should had been adjusted when the units where buffed.