Flight leaving has stopover in same country we left from??

Hi, We are Australian (from Perth) and will be flying to Hong Kong for 5 nights and then fly to Shanghai for 3 nights (just under 72 hrs flight to flight) and then back to Perth. The flight back to Perth goes via Hong Kong (no stopover just transit to new plane). Would this be considered Country A to Country A. Are we eligible for Visa free 72 hrs