Concerto,

What I experienced at check-in is that you usually upgrade for 2 sectors if they have seats..

But if it is done at the gate it is only for one flight...

I was in MIA with my wife last week and wanted to upgrade to F class... ... at check in as was told the message was in the system and I was going to be called at the gate...

At the gate they in fact gave yours F seats to a CIRCLE member...and with no miles!!!
I m "only" TC Gold member.... So even with last minute upgrade you have to be sometimes at the top of the list.....

But anyway the C class was nice and the food good..

Kooks....