[PopskiPPA]

IIRC (I'm working from memory) the Russians and the western allies used different anti-armor ammo. One was better against face-hardened armor, the other against rolled homogenous armor.

The Germans reacted by producing different armor for the western and eastern front.

So it's not a question of changing a penetration-value, you'd have to double the number of german armored vehicles. Later in the war one can imagine the Germans would use the armor that was at hand at the time, ending up with a mix of RHA and FHA on the same front, even on the same vehicle.

As I said, I'm working from memory (reading to much stuff), so please correct me if I mixed up something.