The price for USA city-HKG-HGH/PVG-Canada city open jaw is much higher than last year. If one adds the positioning flight (Canada-USA city or Canada-USA city), the price will be similar to the typical round trip price. For example, I can do IAD-SFO-PVG-SFO-IAD for approximately $600. If you are lucky, you can do multiple same-day changes on your outbound flights to reduce cpm.
The USA city-HKG-XIY/PEK-Canada city route is not as attractive as the last year's USA city-HKG-HGH/PVG-Canada city deal because of the cost for going from XIY to PEK (~$100). If you have a Chinese visa and you have not visited Xi'an. this trip may make sense. For me, I am not interested in visiting Xi'an again, especially, in November and December. If you live in east coast, you can probably find this deal for about $400 (hint: from one of home airports).
Good luck.