72 hour transit visa at Shanghai Pudong Airport

How is the 72 hours calculated at Pudong airport; is it the scheduled time of arrival and departure or the time when we receive the transit visa?
Our flight is scheduled to arrive at 7.30AM on 29/05/2014 and scheduled departure at 11.00AM on 1/06/2014.
If a transit visa for 72 hours is okay do we apply for one at the Consulate in New Zealand or get it at Pudong airport.
Thanks