72hour visa

Hi I think this will be a 2 part question:
But I’m currently in Hong Kong considering to visit friends in Shanghai then head back to sydney after. So my itinerary will be HKG-PVG-HKG-SYD

1. Am I allowed to use the free transit if I’m coming from Hk
2. Because Cathay Pacific needs to stop by HongKong for all their flights, if I return to my originating destination am I still able to use the transit visa, even if I’m connecting to sydney.

Thanks in advance