Re: When did O'Brien lose his commission?
O'Brien identified himself as an NCO to the Rozhenkos, so if he was moonlighting as an officer he had given it up by Family.
Indeed, Mr Rozhenko even recognizes O'Brien as a Chief Petty Officer, despite the Lt. pips on his collar.
"Internet message boards aren't as funny today as they were ten years ago. I've stopped reading new posts." -The Simpsons 20th anniversary special.