That is exactly how mine worked this time and other times. A long time to reach 50% and then suddenly it's done. You're likely goodIs there any way to confirm that the software loaded successfully if you do not have access to the car?
The download said 43% on the app and then when I checked 15 minutes later, it just went to the normal screen in the app, no indication of failure, just 43% to done. It took a little over 2 hours to get to this point, but I am downloading over LTE while car is parked at the body shop.