What if your dev bank is fat and you are on a coach flight that is less then your scheduled ticket...at check-in the screen says you can "upgrade" to a seat with more leg room for $X, which when combined with your dev ticket price still keeps you below the cost of the scheduled ticket....can I pay the $X with my FEDEX credit card and then charge that against my dev bank?
It's not an upgrade in class --- just an upgrade to a more comfortable seat.
If allowed, has anyone actually done this...and was filing for this additional expense easy?