China 144 hour visa free transit

Arriving from Bangkok (Thailand) in Shenzhen (China). After staying in Shenzhen for 140 hours I plan to continue my travels by taking a ferry to Hong Kong. After staying in Hong Kong for 7 days I will return to Bangkok (Thailand). I have a US passport. Please confirm that I'm eligible for the China 144 hour visa free transit when I plan this route within the planned time frame. Thanks