explain "out of command"

[dukemat]

could someone point me to an explanation in the rules for "out of command".

I don't under stand why some HQ's are in and others are out.

82nd Div Hq is out.

I have following HQ's out:

82nd div out at 55,61
507 regt out at 57,61
2bn 507 out at 54,62
1bn 507 in at  54,63
2bn 508 out at 58,66
1bn 508 in at 58,68
508 regt out  at 62,67
3bn  508 out at 59,69

all of these HQ's are within 10 hexes of each other and some are in command and some are not.

any help would be appreciated