I just thought I would add some of my observations here from playing the game.
I often assualt without the enemy being disrupted especially when playing as the Russians.
They quite often seem to be facing small German units in bunkers or vehicles of some discription and are unable to fire at 1 hex range. But if you assualt these units with a reasonably large force it often seems to work. Sometimes you have to assualt with several units seperately, but in the end they generally seem to succeed.
So I hope that may help you a little get over the maths of it all, as like the others I don't understand any of that either, I just haven't a clue.
Cheers,
Gordon