Regarding the "3rd country or region", does this also apply to the flight to Hong Kong?

This special case is not specificly mentioned above, although HK is mainland territory. My plan is to book a one way ticket from ICN(Seoul) to PVG(Shanghai), and then book another ticket PVG(Shanghai) to HKG(Hong kong) which depatures within the 72 hr time, and then buy the ticket back to Seoul later on. In this case, does the 72hr Visa free policy in Shanghai apply?