Slightlygoofy is right--there is a "hidden" charge to the DDP.  On the plan, you must have a non-discounted room and at least one day of park ticket per person.  You could have gotten a slight room discount.  You could have had an annual pass, FL resident pass, or whatever you might qualify for.  
However, I'm not aware of any room discount that equals the $ value of 
free dining for 2 adults.  Even if it did--say you could have saved $75 on your room--you still have all the food free!  It's a great deal no matter how you cut it.  If you have APs, save your one day tickets!  I wish we weren't in school and could do it!