4th FastPass + ?

[disneyluvrsX5]

So can we get the fourth FastPass immediately after we use the 3rd or is it at the end of the hour for the window?

Also, is it completely impossible to get a 4th FastPass at say 9:00 p.m.? At Magic Kingdom on a 1:00am night. Just trying to figure out how this is going to work.

 

[kmb584]

So can we get the fourth FastPass immediately after we use the 3rd or is it at the end of the hour for the window?

As soon as you use your 3rd.