I have had some luck getting a 4th FP+ for top tier rides like FEA and Soarin by constantly refreshing the
MDE app page for the time I want - and I do mean constantly. As soon as it comes back to say there are no FP+ for your party, refresh it again, and again, and again. So many people see that there is nothing available and just quit after one try. I may have to refresh 50 or 75 times or probably more (I don't count, and I try to do this while I'm sitting somewhere), but almost invariably i will see times pop up as I do this, most of which will be for times I don't want and which will be gone on my next refresh. With persistence, I very often get something close to the time I want. During our December trip, the three of us had our third FP+ for FEA at 4:45 PM. I wanted it to be a bit earlier, so I did my incessant refresh routine and got it moved to 4:15. As soon as I tapped in for the FEA FP+, I started looking for Soarin, again by constantly refreshing (I did take time to enjoy the FEA attraction). I got a FP+ for us for Soarin for 4:30-5:30. After we used the Soarin FP+, I refreshed my little heart out and got a FP+ for Test Track for a little later. My daughter and I also rode Toy Story Mania at the Studios three times in an afternoon by doing this. Of course, I have had my failures, but I would say that it works more than half time time.