shanghai pudong airport arrival from moscow/departure to tokyo, 72-hour transit viss

I'll have a Congress in Tokyo and my trip is via Moscow to Shanghai (Aeroflot) and then to Tokyo (China Eastern). Arrival from Moscow is on 1 June about 10.10 h, departure to Tokyo is on 4 June about 12.00 h. I'll stay in a hotel downtown Shanghai. My calculations are that I'll be in Shanghai less than 72 hours, entering Shanghai about 11.00 h on 1 June and leaving Shanghai about 10.00 h on 4 June (according to the stamps of the passport counter at the airport). I have my flight tickets, but if arrival and departure hours must be considered, my stay should be 73 hours and 50 minutes. However, the time for passport registration upon arrival and check-in before departure shall decrease, for sure, my stay in Shanghai to less than 72 hours. Am I allowed to use the 72-hour transit visa that way or there could be some problems?