72 Hr Transit Visa Exemption. I am a Canadian citizen with Canadian passport.

I am receiving conflicting advice,very close to my departure, re qualifying for 72 hr transit.
I will fly Toronto to Shanghai, stay 2 nights, fly to Hong Kong for 2 nights, then return to Shanghai for 2 nights and fly Shanghai to Toronto.
My question is "Do I qualify BOTH WAYS to stay in Shanghai under the 72 hr Free Transit?"
I would really appreciate a reply at earliest convenience as I do not have time to get one and would have to cancel part of my trip. Thank you in advance.