Hello, Bill!
My guess is that you might have heard about Tables in Wonderland Membership, rather than an additional Disney Dining Plan.
I've included a
link to a tiny little description of Tables in Wonderland Membership, which can be found on Walt Disney World Passholder Program's webpage. Currently, if you are an Annual Passholder, you can purchase membership in this program, which offers its members a discount of 20% on all food and beverages at participating restaurants. Membership, like annual passes, lasts for one year. On the above-mentioned page, scroll down to near the very bottom and look for the section entitled "Tables in Wonderland" membership for more information.
Although not a perk offered to Disney Vacation Club Members, many members are able to purchase Tables in Wonderland Membership because they are also Annual Passholders. (Our Annual Pass discount, after all, is pretty impressive!)
Thanks for asking this great question! Please send any additional questions you may have about vacationing in Walt Disney World! I love to help!