Thanks. You're right, its more appropriate than other letters that I'm sure get sent out. I wasn't too attached to Indiana because my research interests took a bit of a change in the last year, but I still decided to see them out. Nonetheless, my POI there was pretty flaky with emails, making me wonder how he handled advising duties (he would set up phone meetings, then flake, then email 3 weeks later apologizing profusely, reschedule, then flake again).