Remember that the reason for hans floating resources was that he more or less had reached full pop-cap. Granted that is no excuse for not vetting up his units. And i do think if he had simply vetted up those two Panzer IVs that he could have taken on andyisrippin and probably taken out most of his force. But for some reason. he didn't use one of the primary abilities of the doctrine.
As for the Tiger Ace itself. The major factor in it not really doing an awful lot was the fact that hans ignored a Vet 3 Field gun which was allowed to knock off 50% health in a short period of time

That and he then proceeded to loose all pioneers. The IS2 as such merely demonstrated that it can resist the Tiger ace Reasonably. But in a one on one between the two with the Tiger Ace at full health. The tiger Ace would have won.