Multiple cities, different layovers

I have received a few 'you probably need a visa' to 'you do not need a visa' replies from phone calls.
Here is my current plan. Can I change it to make sure I do not need to apply for Tourist L visa?
Canadian passport,
fly into Shanghai, less than 72 hours, fly to Philippines.
2 weeks later, fly out of Philippines to Beijing less than 72 hours
Beijing overnight train to Shanghai. less than 12hours in Shanghai and fly back to Canada that evening.

Both areas are considered in the 144 hr zone. But I am understanding that I cannot visit 2 zones in the same 144 hours, is this true?
Confused.
Thank you.