How can I count 72 hours.

I am planning to go to shanghai from bangkok 27th of nov, flight will arrive 11pm of 27th.
and i am about to book the flight shanghai to seoul leave on 30th 1pm.
is it still on 72 hours?
to sum up.
my flight from 27th till 30th.
from bangkok->shanghai->seoul.
so as i know they count the 72 hours from 28th 0:00 right? then is it still 72 hours as i understand.