it should take 15 hits to kill a tiger but when they are in point blank range then ya it could be killed by two shots.
So you want an arcade game, not a simulation?
The M4 we have is armed with a British 17lber that could and did kill Tigers in one hit, at range.
Those of you asking for consistency, that is wrong. If it were consistent and not seemingly unpredictable due to slight variances, then it would be an indication that it is too simple and wrong. HiTech has said that the armor model on tanks in AH is one of the most detailed sections of code. That doesn't mean it is right, but at least know what you are asking for and why things work how they do.