Tyro3

I am trying to understand this, is there a formula to calculate number of men that a certain officer can command without losing efficiency? In my latest run through I have two lt. colonels one with command of 41 and efficiency of 37 and he is able to have 11 more men than a lt. colonel with a command of 41 and efficiency of 40, I would think it would be the other way around, am I missing a piece of this puzzle?