I am just over the 72-hour stay but according to the rules above I should be fine right?

Raj, according to Beijing Immigration Office, the situation in Beijing is different from other cities. The 72 hours there start from the time when you have gone through the formalities of applying for the free transit policy. So I'm afraid your layover time is a little bit longer than the allowed stay duration. You can confirm this with Beijing Immigration Office by dialing 0086-10-56095400.