I have the RC Rewards Card and would plan to use the card's Cub Level Upgrade certificate during a stay, but when I include the Z34 code in the Special Rates box to check availability and price, I get the following message: "The special rate you selected is not available for the dates you requested," which indicates to me that you cannot use the certificates for a club upgrade at this time but I probably need to call reservations to confirm this. Has anyone else experienced this?