So you consider an unit that has 25 % more hp and penetration with only slightly less armour and dps to be equal tot he p4. dude test it out yourself a battle between a 85 and a p4 is 10/10 in favour for the 85.
Test yourself, T-34/76 vs Panzer IV, the latter wins 10/10.
In a vacuum, Panzer IV is outmatched. In reality, it has better vet and Axis only support items like Panzerschreck or Panzer Tactician or Blitz so it can easily get away from situations where others are not around to make up for its minor disadvantages, so it makes sense for the Soviet tank to have the better stats especially with Panther around. Compare to the Panzer vs 76 matchup where Panzer has both advantages. Axis is or about should be supporting fewer tanks with your great support and getting the best out of them but you don't have to do that against Soviet stock vehicles.
It should of course cost as much as it does in the single Advanced Warfare call in. Consider that. And check my thread for more elaborate arguments on this.