Unless the team is absolutely loaded with studs and more importantly, arms. I wouldn't bother booking the extra night. You have to go 7-0 or 6-1 to advance and it is set up where there is already top team in each pool.
Also, they actually play 7 games in 6 days with the first round of the playoffs starting on Wed. So when he played for a lesser known team we booked Wednesday flights.
When he played for the big boy program we stayed the extra night and booked a late Thurs night flight. His last WWBA they went to the quarterfinals and I was on the phone in the middle innings looking for a place to stay so he could stay for the semis and finals the next day. Of course as soon as I found a room they blew a lead in the bottom of the 7th then again in the 10th.
Book for what it necessary, you can always find a way to make something else work if you make the playoffs.