Traveling home tonight on a 331, the car had tables between the facing seats. As these are (presumably) mostly commuter units this seems a little odd as it makes it harder to get in and out of seats quickly and to place bags. I've rarely traveled on 331s up until now - it seems I usually hit 333s or 322s which don't have tables. Is this a usual arrangement or do units differ? It does not seem a good layout for commuter trains.