I figure it's obvious that after you have used your 3 scheduled FP+ you can get a 4th (based on availability of course) but are you able to get that 4th one after you have used the 1st FP+ and have yet to use your other 2 scheduled FP+ OR must you use all 3 pre-schedued ones first? If the latter is the case then I could see it being more difficult to score a 4th FP if your 3rd FP+ is a late afternoon window.