According to in-game chatter from players, they kind of nerfed the effect of HE across the board. I haven't confirmed that, but that's what folks were saying.
And how in the hell does the AMX-40 go 50? I'll have to check again, but mine is fully upgraded and is dog slow, certainly nowhere near that fast IIRC. Or maybe it just seemed slow. But the French tank guns through TIV are horrid.
EDIT: I just checked, and while the info for the AMX-40 says 50kph, it lies. The tank goes 20, 21 at most. It is indeed a slug.