Originally Posted by
csycsycsy
Possible clue to OP's route is their username, as dnw has figured...
Assuming OP has booked 2xJ/U for 1 parent and child, and will book the W/P for other parent and child, I wonder if OP's chance of getting a POUG is affected by having a child in the booking.
Can't upgrade an avios/P booking to U with cash but can upgrade a WET cash booking into U with avios, and I've observed as long as there is "I" inventory, doing an avios upgrade into U does not remove U space, as long as U is >0, so it's possible to have more than 2 Us, even ex-MAD.
Data point on this. I cancelled the 2 U seats and I booked 2 PE (P fare class) seats. Having checked that 2 U were available, I called them to upgrade from P to U but it appears that while they were in the process of reserving the seats for the upgrade, the 2 U seats (that were there before) disappeared, so I guess that either this "workaround" doesn't work or the "I" inventory was full or that "I" is only allowed for cash bookings