We did something similar to Dean's suggestion. While we were on the crusie this past February, we made reservations for cash for next year (really good cash discount while on the cruise to re-book). When the point schedule came out, we compared the cost in points vs. the cash cost. Needless to say,we didn't change the reservation to points because of how many it would have cost. Doing it this way at least gave us the option.
HBC