Maybe the "Deluxe" Plan can save that much if you got a discount on it, but if you are paying full price for it at $109.53 per adult per day, 5 days is $547.65 and includes 15 TS credits and 10 Snack Credits (and refillable mug). 15 TS meals is A LOT of food. I just cannot eat that much food. If you use a counter service (instead of a Table service) you are getting a lesser (in cost) meal than you are with the TS and as such it makes it that much harder to make it "Worth It" Even with the snacks. The Snack Credit basically maxes out at $5.00 so your 2 snacks a day is (at best) $10.00. Using Fuzzy Math, that leaves $100.00 A DAY for meals (PER PERSON) You claim a savings of 25% so that means you get the "Value" of $125 out of the $100 remaining (over OOP). Even at Disney, a $100.00 of food is A LOT of food.
We struggled to use all of our Standard Dining plan (1 TS 1 QS and 1 Snack per person/day) for our 9 day trip in November/December. We did do character dining, Signature Dining, etc... We struggled to eat all the food sometimes. In the Hotter months, Most people eat LESS making it harder to get the value out of it. If you don't use it, you lose it (and it's value).
All that being said, I am not saying that someone cannot get (or find) value in the DxDP, but the value comes more at convenience then it does saving money more than anything else. Don't take my word, Check out
http://www.wdwinfo.com/disney-dining-plan.htm as they did a nice analysis.
Under the Deluxe Dining Plan review:
Again, their conclusion:
For anybody else, this plan is almost certain to be too much food, too much money and require too much time.
If you are saving 25%, then good for you. I think for the average Disney visitor considering the plan would never even come close to saving that, nor would most save 15% on the standard DDP. I am guessing (based on what I have read and my personal experience which is, albeit limited) that the "Swing" is plus or minus about 5% or less for most folks and that is on the standard plan.