Originally Posted by
Smirnoff
Not from my experince. You only need U to be available, and then you can change according to the rules of the T ticket. You don't need to upgrade to W. (At least I didn't).
But the OP seems to be experiencing precisely this. And I had a play with my own MFU, looking at changing the return, and saw the same - over £1,000 to change departure time, with U availability on the alternate flight.