Late check in

I had a surge price route for $126 for a 3.5 hr route. It started at 6:15 a.m. but I would not be able to make it to probably 6:35 a.m. I was wondering what's the latest anyone has ever checked in after their start time. I didn't take the route because I didn't think I would make it in time and not sure if they would still allow me to do the route.