72 hr or 144 hr visa free exemption

Hi,

My husband and I are visiting HK from Sydney through Shanghai in the beginning of September: arriving Sept 1 to Shanghai, flying to HK on Sept 3 rd, coming back on September 5th with 3 hr overlay in Shanghai and back to Sydney. Route looks like this:
Sydney-> Shanghai-> HK -> Shanghai->Sydney

Will either 72 or 144 hr free apply?

Thank you!