Can I get two 72 hour Visa-free transit for two different stops?

My family and I (US citizens) will be traveling from Tokyo to Shanghai (spending less than 72 hrs) and then going to Hong Kong for 24 hrs, and then onto Beijing for about 36 hrs before heading back to the US via a stop in Tokyo. Would we just get two 72 hour Visa-free transits for these two stops, one when we get to Shanghai and the other when we arrive in Beijing? I would assume that is allowed?? Thanks!!

Brett