Originally Posted by Twickenham

Yes, that is correct. For instance, just this week I booked 2 Europe 1 tickets, at the current 90,000 miles level, for next summer. As long as I do not make any changes after the new mileage levels kick in, I will not have to pay the difference; however, if I make a change after December 15, the mileage will be recalculated and I will have to cover the distance. As I managed to book our perfect flights, that won't be happening...