Do I need another visa?

Hi, I am an exchange student in Shanghai and got one with two entries. I have bought a flight ticket departing from Shanghai (Pudong Int. Airport) to Tokyo (I will spend 4 nights there), then I will get back to Shanghai (Pudong Int. Airport) and with the same airline company, however, on a different airplane, I will head for Bali (Indonesia). My question is since I no longer have two entries but just one left, can I take the benefit of this 72-hour transit visa in case I don't leave the airport (Pudong Int. Airport) ? Therefore, can I take benefit of this 72-hour transit visa ? Thank you so much in advance!