I'm considering booking a ORD-PVG-BKK itinerary and would like to take advantage of the TWOV, but I would arrive PVG at 2:50 and the departing flight leaves 2 days later at 5:20, slightly 3 hrs. over the 48 hr limit. If, for example, I arrived at the airport and checked in a little early to be within the 48 hours, would that be allowed? Or is the time strictly measured from the time one de-planes to the time one re-boards?