Pulling up an old thread to keep it neat for future searchers.

I just reserved a room at the Marriott at Dulles using a Cat 1-5 certificate from my credit card. I want to use it as a "Park Here, Fly There". I saw the cash booking rates had that package for a $25 premium ($124 vs $99). Can I call Marriott or the property and just pay the $25? If it has cluster potential I'll probably just cancel and re-book on a cash basis. In my award notification I saw it says under additional charges:

I'll be gone a week, so if I am going to potentially pay $63 ($9*7), I'd just assume pay $124 and keep the certificate (and earn the points).