Can't say I'm that familiar with the traffic flow between LAX-YVR, but AA is certainly extra connections into LAX. Seems like a YVR-LAX flight could connect into LAX-HND and other Asia flights but no way would AA ever go LAX-YVR-HND. Its not open skies. AA was only approved for LAX and can't change cities without approval. Beyond that, the attraction is offering the LAX the quickest service to downtown Tokyo. An extra stop certainly doesn't do that.