Booked an Amex reward flight ADL - BNE - ADL and was happy to pay $39.00 each way and upgrade to Economy X.
When offered the chance to bid for J, I decided to have a crack and offer $120.00 each way - $20.00 more than the minimum.
I just received confirmation that my ADL - BNE upgrade has been successful. With a $39.00 X refund coming my way (I'll ring upon my return and request it) I figure that for an additional $81.00 on top of the X cost it's worth it.
Let's see what happens for the return leg.
For the record, J is now showing as a cash fare of $1,105..01 with 1 seat at this price!
