Travel plans - am I covered with the 144 hour visa

Hi,
I'm flying London to Shanghai on Dec 22nd...arrive on the 23rd and 09:25. I depart for the Philipinnes on the 26th Dec at 16:30 (say 70 hours - but over the 3 day free transit). I return back to Shanghai to Catch my return flight from the Philippines on 2nd January and depart on the 3rd. This will be within the 144 hours, but am I allowed to do this due to leaving and returning ??
Thanks
Scot