Transit flight to Amsterdam

Before arriving in Shanghai I booked a return flight Amsterdam to Shanghai and then Shanghai to Amsterdam (Flight on July 23rd). I had a double entry VISA but due to an early business trip I left the country early on my first entry and it will expire June 23 and cannot stay until my flight on July 23rd. I will therefore leave China on June 21st for 1 month and go to Vietnam and I would like to fly back on July 21st and get a 3 day transit since I will fly from Ho Chi Minh to Shanghai to catch my flight two days later to Amsterdam on July 23rd. Can I get a 72 hour Free entry even though I originally booked a return flight Amsterdam to Shanghai but now flying from Vietnam to Shanghai to get my flight back to Europe ?

Thanks for the help