You can drop one or the other. I really don't recommend LOS though. If you use a ticket broker (I use Paramount) you can come out ahead. Also, if you end up not in the park one day, you can save that day fo another time and not lose out. I know that isn't peoples initial plan but we had one of the kids get sick and so I stayed in the room with her. It made our LOS's very expensive when you didn't use a day.
Good luck
Sandy