You are right in that it pretty much exactly showed the behavior of modifying the reservation. The booking now shows 1 room, at the prepaid rate. Which is what I wanted to end up with... but the kicker is that I don't believe that I modified the existing reservation. Until you just mentioned this I wasn't aware that changing to a different/lower rate would have been an option for an existing reservation.

When you do make a change, does the email confirmation mention that it is a change to an existing booking? Or just the typical "Reservation Confirmation #<number> for <hotel>"?

Thanks, I was considering calling the hotel directly but this may be a better way to go. Would there be a way to contact support through email? I'm not in a rush and having these kind of matters written down/confirmed is always a little easier in case this matter does pop up during check in.