The flights can only stop in one Chinese city

I am confused about this stipulation. I am flying out of New York, onward towards India. My flight has a short layover in Shanghai for a new hours and then goes via Kunming to Kolkata, India. My layover in Kunming is about 9.5 hours. Am I able to go out of the airport in Kunming and use the 72 hour TWOV (I am a US Citizen) to check out the city or would that not be permitted because I have a layover in Shanghai first? Thank you in advance for your response and assistance with this question.