Quick question on earning CR1's, my understanding is that 2 CR1s are deposited after you fly 10k BIS miles, per quarter.

Looking at the summary it appears the miles from a failed sub-10k quarter are carried over to the next quarter. Or, is the quarter is a "rolling" concept not strictly Jan-Feb-Mar?

And if miles from failed quarters are carried over, what about superfluous miles (in excess of 10k) from successful quarters?

Anyway add me to the list who have flown 10k BIS miles in 2007, awaiting the earned upgrades.