Lt's and Captains don't gain experience if they are not "nearby." The distance I'd guess would be around equal or less than the range of their vision.
Ok, so it's about the experience but what I was writing about is the bonuses for the units.
All officers have (Do Major has as well ?) bonuses for infantry units?
Sure Majors get their own experience as well.
There is still a little mess in my head on it, as there is no documented data for this abilities.
I mean bonuses given by officers or the required distance (just to be on the field, be "nearby" etc)
The "nearby" definition is important for both the bonuses and own experience.