I am not sure if I am allowed the 72-hr transit with this itinerary

Hi, I am coming from New York City and would like to explore the Hunan province a little bit on my way to Bangkok and Manila. Here's the sample of my itinerary: JFK-Changsha-Bangkok- Manila
Then Manila -JFK. But I think going back to US, it will stopover again to Changsha. Please help. Thank you.