72 hour visa. I am a US citizen and my husband a Mexican citizen.

Hello,
We are flying from LAX and have a 5 hour layover in Beijing then go to Thailand. From Thailand we return to Beijing for less than 72 hours( a quick tour of the Great Wall) and then fly back to LAX, do we both qualify for the 72 hour free transit? I have asked the airline and travel agency and they have me different answers.