Outbound and Inbound stopover in Beijing

Hello,
I'll travel from Vancouver (origin) to Beijing (stopover; stay for two days) to Singapore (destination). I'll stay for two weeks in Singapore and on my return, it will be from Singapore to Beijing (stopover; stay for two days) to Houston. Do I qualify for the 72-hour free transit both ways (that is, from Vancouver to Singapore, and from Singapore to Houston, both with stops in Beijing)? Thank you.