By my reasoning, it is absolutely possible that this happened within seniority. Starting at the top of the roster going down, you're initially going to have a Q quota not filled. So IAH being much more preferable to EWR, the first bids you can award any Q spots to will be 9L guys, who will probably have IAH before EWR. That goes on until the quota is met, then now you can go back to the top of the list, and start down, IAH vacancies are gone, so EWR gets the rest. Seems to me to be exactly how the quota system was meant to operate. You can't look ahead to the end of the bid, say "the quota will have been met by the end, so I'll just award the first seat to anybody," because then you will be awarding Q seats to somebody before the quota is met.

I do want to go on record as saying that I'm not sure that the quotas are really in the spirit of "one list, one voice" to begin with, but I wasn't part of that decision. It's more like "one list, one voice - except for those guys."