Maybe I am missing something here, but when I looked at the OW Explorer and priced a PER-TXL-LHR-YYZ-LAX-PER the prices for economy come to about $6000 each. You can book 3 itineraries, a return PER-TXL but back via LHR, a one way TXL-LHR, and a return LHR-YYZ for half that price.
Am I missing...