"Wrapper" trip, 72 hour visa free transit in Shanghai

So I have one RT flight from Dallas to Shanghai for 8 days. Within that 8 days, I've booked another RT from Shanghai to Japan. I'll only be in Shanghai for about a day on either end of the trip. Will the outbound flight from PVG to NRT (scheduled within 72 hours of initial arrival to PVG) count as the "third" country on either end?

Basically, I'm assuming they don't care whether a flight's on one booking or another, just so long as my butt's out of Shanghai within 72 hours (to a third country) of me landing.