I will add that I seen, but can't find it now, a diagram which I believe fprado's site had. This diagram was from a Tiger manual to all appearances. Some of the print of the diagram was very tiny, particularly the ranges it was stating, but the target showed some of the fire coming in what appeared to be between 30 and 45 degrees from that longer range (probably 3000yds).
While many of the fire demonstrated was at near flat trajectory, the longer ranges were considerably arched. It seems a lot of people would not believe what that Tiger diagram showed about the arch of their further shots. I'm of the thinking that this is because a lot of nations may had refused to train their tankers to fire at longer ranges, due to not having powerful velocity in the first place, and also because it was easier to train people to fire on flat trajectory only, plus of course the German superiority in optics had to aid in the idea of firing from great distances.
What this means, is that if the shell were to hit in a 30 degree trajectory, that suddenly the tank with the 30 degree slope is in the worst slope possibility. Some monthes ago I mentioned that in such an instance a zero degree slope on a tank would be better, that position was countered by the statement that if the 30 degree shell had not penetrated, that it would bounce for the most part down instead of up (as with flat trajectory shots on sloped armor), but the more I think about it it shouldn't matter a whole lot (I could be wrong of course).
Let's say the upper hull is hit froma 30 degree shell on a zero degree hull. On such a hull, it will either bounce into the ground, the shell would've been largely damaged on original impact, or it would hit a lower portion of the hull with less impact, where hopefully the target had just as much hull armor.
OTOH, if a flat trajectory shot were to hit a hull slope of 30, we are told it will bounce up. While there is less things to hit up, than down, there is still the chance that the turret will receive the bounce or the gun itself.
What I imagine, with a shell hitting at 30 degrees, is that there are some instances where a tanker in a Tiger, for example, was actually better off firing on well sloped tanks, such as the T34, from a further distance, where the slope was all but nullified, assuming the loss in some accuracy was worth the gain in penetration through a flat hit.