I notice when trying to trade underperforming officers in at SFA it excludes a number of officers from being able to be used.
I tried to make heads and tails out of the logic and reasoning to include seeing that the ones you trade in it says must be civilian, ensign, petty officer, specialist, or technician for the green ones in the case I was trying to use them for.
Unfortunately it would not give me the option of choosing numerous ones that I wanted to dump.
I thought perhaps it might be that you can't use the ones that already have a lock on them which in fact were the ones I wanted to get rid of, but that was not it because it would let me choose some of those.
The only other things I can think of is either it won't let you use the ones you get as rewards for tiering up in the various Commendation catagories, or that its some sort of bug.