Stealth_Eagle: You were right, it's bugged.
How do I know? well the bombsight is essentially the same as the one in the sparviero and I know that bombsight very well, used it many times in old IL-2. It's very easy and straightforward to use. Just set altitude and velocity and slip if you need to compensate for any side winds. In the Br.20 I set everything correct, altitude and TAS (true airspeed) but still the bombs fall way to early, it's a shame really.