I prefer compare pen/armor values than pure values, when talking about performance of similar units.
Pentration from mid to frontal armor values:
P4 115/234 (vet 3)
Sherman 130/160 (vet 3)
Cromwell 120/160 (vet 3)
Then let's count chances to pen frontal armor:
P4 vs Sherman - 115/160=71%
P4 vs Cromwell - 115/160=71%
Sherman vs P4 - 130/234=55%
Cromwell vs P4 - 120/234=51%
That sure is one biased comparison if I ever saw one. How about we take their vet 0 performance to compare and not the vet 3 one which obviously favors the Panzer IV because of its armor bonus? Why would you take a relatively rare scenario (all tanks vet 3) for a comparison?
I wasn't comparing Panzer IV penetration to Allied medium tank penetration anyway, I was comparing it to the StuG's. Which has 100% chance to pen mediums at all ranges and is much better versus heavier armed targets. There is no reason to further nerf the Panzer IV penetration (which I was responding to), because it is already quite bad, especially compared to the StuG's.