Yes it does. We've played around with numbers. If we had to pay for the dining plan we would not purchase it.
There is a calculator that I believe All Ears has to see if it pans out for each family. Time and time again they say Disney Wins if you have to use 2 dining credits for one meal, it would be cheaper then to pay for that same meal out of pocket if vs buying the those 2 credits, (obviously free is different.) Our issue is we don't eat dessert normally with a meal and at table service we often have an adult beverage and that negates the free standard beverage cost cause we don't get it. Dessert for a family of 4 generally about $40, now add tax and tip on that. It would never be beneficial for my family if I paid rack rate.
But with my DS we get the plan at a 50% discount. Last time I went to see him I believe it was $25 a piece out of pocket for the 1TS 1CS snack and plastic mug. That was well worth it.
When my DD and I went down discounted we only did the CS meal plan cause we did not want to be tied to ADRs like I am when I am vacationing with DS. I think it was just over $15 day for 2CS, snack and plastic mug. Again very well worth it and sometimes we'd use that snack for our breakfast in the morning and no tipping.
I only did the DP once without a discount and it was worth it but times they did a change down south. Back then we had 1TS, that included the drink, appetizer, entree, dessert
and tip plus 1CS 2 snacks and a mug. First the tip and appetizer went and it was $1 cheaper
the next cut was tootles to one of the two snacks. So no, I would not pay rack rate for it but at 50% off heck yeah.