72+ hrs visa exemption

Hello,

I plan to fly Taipei to Beijing on Friday 13th, arriving at 1130hrs, and leaving on Monday 16th at 2100hrs Beijng to HongKong, is this possible with the 72 hrs transit permit exemption?

I read the 72hrs start the next day of arrival, and ends at 2359 on 'the third day' of the permit, is this correct?

cheers,
Claudia