Has that been tested with data from the game? In theory those factors matter, but wouldn't the velocity drop of a projectile that followed a trajectory leading to 90 deg angle at impact be too slow to penetrate 80mm of armor? At table showing the angle at impact of the incoming round with corresponding velocities, by distance fired (both on level ground) would be helpfull. I could make one up from first principles, but I'll bet the gunnery fellas in here have something already.
Thoughts?
Deflection is a bigger issue than AP. In the case of the Panther's front hull this is the case more often than not. Like I pointed out earlier, take a buddy in to the DA and 1 up a Panther and the other up various tanks and start from 600 yards and work your way back to 2000 yards. You will find that vs the M4/76 the Panther will do very well up close from 400-800 yards, and from 1600 yards back. In the case of the M4/76mm at 1600 yards vs the Panther the AP ability and trajectory both behind the curve and unless everything is perfect for the M4/76 it is going to have a very difficult time defeating the Panther from the front. In your testing, do your best to get the incoming round to be a direct head on hit from the front and let the armor speak for itself. At the closer ranges the rounds will ricochet or defeat the armor. At longer ranges 1 of 3 things can happen (ricochet, be absorbed, or defeat the armor).
I've done quite a bit of testing in the DA with squad members testing out the better armored tanks vs various AP rounds. The King Tiger and Tiger are truly the kings of the battlefield in terms of armor, and the Panther is close behind in terms of frontal hull armor at particular ranges (front turret armor on Panther is every bit as good as Tiger). When I am sitting at 2000 yards from an group of enemy tanks, I almost have no fear if I'm in a Tiger or Panther. Only the KT (extremely rare away from a defending gv base), the Firefly (rare in general), the Panther (less common), and Tiger (less common), are only a threat thanks to 2 factors: sights and AP ability. If T34/85 engages me at 2000 yards he truly is peeing in the wind because he can barely see me. The Panzer IV's and M4/76 and M18 are a threat thanks to their AP round, but it is like expecting a lightweight boxer to throw a knockout punch vs a heavyweight boxer, meaning the impact needs to be very close to °90 for their round to defeat the Panther's front hull armor, and the Tiger has 102mm frontal armor so it is safe regardless.
I'll take this time again to invite anyone to PM me their email and I will forward on them a spreadsheet showing gv data, it make be helpful to a great many people. It has info showing AP ability, HE ability, rate of fire, turret traverse speeds, turning radius, acceleration speeds, armor, MG's, smoke ability, ammo capacity, etc, etc. It is in .pdf form and any and everyone can pass it around and post it where ever they'd like.