yes - when casualties are allocated, crew-served weapons will occasionaly get additional kill(s) added for the close-bunched crew c/f a rifle section which is considered deployed tactically across the entire hex. It's always been that way in SP-series games.
I think that the casualties taken from any hit should be increased. Every time I fire a high-accuracy shot from one of my Abrams or with a good ATGM like TOW, I only get one enemy casualty, if any at all. IMO the Abrams is accurate enough to kill an AT gun in one shot.