I was wondering if anyone had tested
the commitment from here with a redemption flight:
If you choose to change your flight, you will be entitled to choose an equivalent seat on your new flight. If you change to a lower priced seat, we will be unable to refund you the difference.
Specifically, our 4 pax redemption booking is on 2 PNR to allow use of 2-4-1 vouchers in different accounts. I can select upper deck 744, but spouse can't unless we pay. I don't mind paying as long as we still get seat selection if we decide to move to a different flight also in CW.
Does it work that way in practice?