Yap dont forget allies also have strong AT rockets strafe. and brumbar has to hit larger infantry squad.
Therefore the concentration on brumbar fast decrewing ATG is misguided. Imo it is as fast decrewing as centuar, kv8, comet, even shermans.
my brumbar is used more to clear allies dig in mg or sandbag infantry. or to protect my paks as they fight against 60TD or simply a deterrance against allies infantry blob play.
ATG is 2nd secondary for brumbar, only when i see allies ATG are too far unprotected then i try to move in.
Also im sure manual firing brumbar on the move, will cause the shot to under/over hit most of the time
A doctrinal ability should not dictate the balance of a stock unit. If that were the case, we could nerf the Brummbar to the ground because Ostheer already has frag bombs to deal with infantry blobs.
But back to the point: I don't have any tests or data, but I am fairly certain that only a KV2 can reliably deal with an ATG. A Comet won't wipe the ATG from range 20-40 without getting hit hard himself. The phosphorus can deal some damage, that is true though. A Brummbar can do it though. Usually two shots are sufficient. The main point however was that you cannot reliably counter the Brummbar with anything else than a TD. Mediums are unreliable, ATGs will heavily bleed you or get wiped and bazookas are probably the worst thing to get in this case.
Moving will increase the horizontal scatter from 2,5 to 5, which allows for misses but is still a lot better than any other tank even while standing. Angular scatter goes up from 6-12 which is about average compared to other vehicles. Angular scatter takes less effect though on smaller ranges, and the Brummbar excels if it can get close. What makes it miss is rather the Brummbar targeting a model at the edge plus the travel time.