Originally Posted by Kiwi Flyer
Tools such as GCM and Flying Fish are good for giving an indication but are not the final word. The airline's mileage is what counts and this can be a little more or less than these tools.
Where there is a mileage limit there usually is no grace overallowance given.
I used the Sabre CRS. So AA's calculation will be identical to the above mileage.