Originally Posted by
evilbrian
Most importantly, there appears to be no advantage to buying flex instead of saver, other than the increased number of tier miles, as the upgrades for flex and saver both come out of the 'D' fare bucket.
On routes I buy flights, flex fares are changeable and refundable which is a big difference to having a change fee and being non refundable
Also, points requirements for upgrades are lower for flex fares