I found it very useful. I was arriving at the Sheraton in Harrisburg, PA at 4AM after driving from JFK. 55 hours beforehand I emailed my Ambassador to ask for Your24 check-in. She was not working so one of her colleagues caught the email and followed up with the property. They acknowledge the 4AM check-in was taken care of. I arrived at the property at 3AM as I'd made better time than I expected. No problem checking in at 3AM. I didn't inquire about an upgrade as I was pretty tired. It was a week-long stay but the room was pretty big so I didn't inquire later as to whether there was an upgrade available for part of the stay.

When you were upgraded at the FD did you try to reconfirm the later checkout? Did they push back? Did you ask to speak to a manager or contact the Platinum Concierge?