Originally Posted by
notquiteaff
Potentially a different scenario, though. As danville 1K points out, if the CR1 cleared (even just for part of the entire trip) prior to the e500 window, then it should not be possible later to switch it to e500s. The CR1s have the advantage of clearing right away with availability.
Absolutely true. That's why it's tricky when only one segment clears and you have to decide whether to use the upgrade instrument with the chance the other segment will not clear.