Join Date: Sep 2006
Location: YVR (well, more YPK...)
Programs: WestJet Dollars, BAEC, Aeroplan, AirMiles, IHG, BW and others
Posts: 477
Probably because the Redemption would be on AA flights and they fly to PVG from ORD and not LAX?
So they won't fly you from YYZ to LAX, then fly you back to ORD (which in airline terms is almost back to YYZ after all), to then fly you to PVG.
If it's on a combination of partner airlines, it will be even more flights and miles.