Again, production flaws. If were going to play that game, the B-29 would be modeled on-fire, zekes would be modeled on-fire, the 262's engines would randomly go, and sometimes your 163 would explode due to a bad fuel mix.
I believe what the russians said was that, dispite exelent craftsmanship, the armor was of exceptionaly poor quality, and welds were often shoddy. By spring of '45, the Wermach was on its last legs. It simply couldn't obtain and manufacture all the materials needed to do things perfectly. So even though the tank wasn't all it should have been, its still more than they would have had if they had waited to make better armor.