I read in different reviews, of different aircrafts, that some testers claim, that the tested aircraft has bad/wrong/wierd flight dynamics. But how can that be? Isn't X-Plane calculation the whole airflow around the aircraft multiple times per second? If someone has enough data of the aircrafts' shape, then everything should be right. And with right engine data everything should be 99% to the real thing, shouldn't it? So how can a tester state, that things are wrong?