72 hour Visa Guangzhou

I will be arriving in Guangzhou on the 28/10/14 at 06.30 am and flying out on the 31/10/14. I am confused on when the 72 Hours commences, as the Registration will be done at the hotel. According to the regulation for Guangzhou the Time would start from 12 am on the 28 10/14. Can you please advise

Thank you