Yes, the defenders were shooting back. Placement seemed pretty good to me; they all had clear line of sight, etc. Yes, my men were within their commander's command radius. And this wasn't just a one-turn charge across no-man's-land. It was several turns of Germans advancing across a few hundred meters of open grass. This was also an "assault", so my men were emplaced in foxholes, in woods. This was a fairly carefully chosen position, and while I could be doing something wrong, I'm not sure what. I try to provide the best cover possible for my infantry, combined with command supervision, and a good field of fire. Beyond that, I'm not sure how to improve my defensive infantry tactics. It just seemed so weird to me to watch these germans advance turn after turn, without taking hardly any casualties. I mean, it's not like they were advancing against early-war Russian conscripts, armed with one rifle and some molotov cocktails . Oh yeah, and I checked the casualties by unit after the battle was over, which I have been assuming gives correct figures, so that is where I am drawing my kill figures.
In summary, it seems that 1), maybe I'm wrong, and my men inflicted more casualties than I thought, due to FOW. 2), maybe it's one of those freak happenings that occur when statistics come into play, or 3) maybe I'm doing something wrong. Anyway, thanks for all your input.