Hsi Chang,

AC*SE have no capacity controls in both J and Y , but once a flight is oversold (even with more existing capacity), the privilege stops, even if there are still available seats in J or Y or both. Doubtless in this case, J was sold out, and MP lucked in with a no-show.

On the revenue side SE have guaranteed reservations on S,Y fares (S are the big seats on domestic 767 to GLA/MAN) up to 6 hours before departure.