You're all forgetting what HEAT rounds cause. It's spall folks. Although a HEAT round would probably cause a small hole, it would make the inside surface of the wall come apart just as readily as a HESH shell due to the spall effect. In fact, most HEAT rounds depend on that to kill armored vehicles and other hard surfaces.

And FYI, a way to increase the flexibility of HEAT shells is to wrap notched wire around the explosive within in order to greatly increase the amount of shrapnel produced.