72 hour free transit Guangdong area

hello!

I will travel to Foshan at the end of August (flying into Guangzhou Baiyun airport). I will be there for less than 72 hours.

Is it OK to arrive and say I would like the 72 hour free transit? I fly from Munich to Bangkok, change planes, then on to Guangzhou. Then I leave 2 days later and fly back to Bangkok, then on to Munich.

Will the 72 hour visa on arrival be OK for this?

Is there a limit to how many times in a year you can have a 72 hour transit?

Thank you!
Jessica