Travel USA-Shanghai-Hong Kong-Shanghai-USA

We have a trip to Shanghai from the USA, Feb 6-13. We were then going to travel to Hong Kong a day later after landing in Shanghai. Then we would stay in Hong Kong until the 12th and go back to Shanghai for our trip back to USA on 13th. I've tried reading other posts but I see conflicting info on whether the 144 TWOV would be possible for my situation. Can anybody tell me if I would still have to apply for a visa? Thank you