That the A20 scores so heavily against fighters in the air to air sphere, as proven via the stats page, simply throws a flag up for me. I believe that AH is a "reasonable" tool, by and large, for measuring basic performance characteristics simulated versus actual.
I don't think you should put so much weight on the stats as proof of much of anything when comparing planes to each other.
I just looked up some recent stats for another plane that has had some pretty dedicated doubters when it comes to it's FM. To put it bluntly, it's been called over-modelled, uber, UFO'ish yada, yada, yada. Now, if we look to the stats for "proof", we'd find that the actual K/D "success rate" of the F4U is-
F4U-1 0.88 /1
F4U-1A 1.23 /1
F4U-1C 2.57 /1
F4U-1D 0.71 /1
F4U-4 2.48 /1
-which could actually lead me to believe that the AH F4U is pretty radically
under-modelled, since the books tell me the F4U held around an 11.3/1 K/D in the war. (I don't actually feel that way, btw)
I also can't remember seeing any articles telling me that it was successful when flown against B17's, Stuka's, spitfires, etc...
In short- I don't think we can use AH stats
or WWII stats to decide whether a particular plane has an accurate FM in AH.
Quite honestly, there are some guys flying the A20's in this game that can make them dance around in ways that it seems maybe they shouldn't. That can be said for practically
any plane though. However, if you don't fly to the strengths of the A20 it really isn't very difficult to shoot down, either. Like with any other plane, it really comes down to pilot skills/errors/misconceptions of E-states, etc...
So- is the A20 Fm correct? I don't know- but I sure wouldn't form an opinion based on how it's used and how successful it is in the game vs in reality. Ah pilots are quite different, and performing at quite different levels and in different circumstances than "normal" WWII pilots did as well...