the Yak is a small target and it can take alot of punishment. After that it would have to be the FW190-D9. One theory I think about is the speed of the target. Something very fast that is pulling away from you will receive slightly less lethal hits than something that is closing with you head on, increasing the impact speed. Small differences (if indeed the ballistics are modeled that well). I think it can swing the balance at times. Doras and Yaks are always pulling away from me.