Efficiency should take into account reinforcement cost. Right now they are kinda useless stats.
Something like, Dmg per MP spent would be a lot more interesting. It'd actually be stats worth looking at.
And why, just why does it count "units killed" for every model but "units lost" is whole squads, it's so annoying. It's almost like they went out of their way to make the stats useless. What the hell is army value anyway? If it's really what it says it is OKW is visibly OP from the very first second.