Dubai -Xiamen 72 hr visa

Urgent
Im trying to get a 72 hr free transit for a french citizen traveling to xiamen from dubai(resident in dubai)
I have arranged a ticket dubai-hongkong-Xiamen & on the return xiamen-singapore-dubai(for the transit purpose)
Is this required or can he get a 72 hr free transit even if he goes straight back form Xiamen to Dubai?

Question 2 :
Arrivig xiamen 11am 1st july and leaving Xiamen 4th july at 2.30 pm, does he exceed the 72hr?