Originally Posted by
dmahon
If you "buy and upgrade" at the same time (i.e. when his miles have posted) does it sell you an expensive Y ticket or does it sell you a cheaper one?
I know that you can "buy and upgrade" a cheap(!) non-upgradeable Club fare to First (one that MMB does not normall allow you to upgrade with miles).
From the Ultimate Guide:
You can only upgrade from Economy to WT+ if your ticket is a Y B H fare. You CANNOT upgrade from a cheapy economy fare to WT+, although you can upgrade from a cheap WT+ fare to Club World. Note that as confirmed by Lyndsay the ‘special’ fare sale seats – if you booked your WT+ (T class) or Club World (I class) fare under a special offer (normally indicated by a big red ‘D’ for Discount throughout Fare Explorer) – are eligible for MFU.