My FP+ day I was having trouble with the system crashing repeatedly as I was trying to book when the window opened (which if you keep up with the DIS is an ongoing problem) so I had two browsers going on my PC and was also using the app on my Iphone. I booked from all 3 places- I was using whatever I could get to go through. It worked fine. It took several hours for them all to be listed on the app, but they eventually all showed up. We had our trip a couple of weeks ago and everything was fine.