changed from QR to BA number via phone, could than select my seats for free for all 4 segments.
weeks later changed my outbound flight and while trying to reserve the seats for these two segments, it wants to charge me (i could still change the seats for the inbound flight, for free)
called again and it seems the "sticky" QR number came back and messed up my outbound flight. changed it back to BA OWE number and can again select all my seats for free.