Hi = does visa exemption apply please advise

We have to fly via Beijing to get to our destination - we could not get direct flights and have to go via China. When we fly back we come into Shanghai via cruise ship at port - we have to fly back via beijing .

We got under 72 hours in shanghai and then start the flight home, but since we have to fly vai beijing we wondered if the 144 free transit applies and we can break the flight and do under 72 hours at beijing, then fly on.