Believe it or not, the alcohol could be the tipping point. If you want or will purchase an alcoholic drink at all of those, you will pay extra if paying OOP, but it will be "free" with the DDP. I have a feeling the online calculator is not factoring that into the equation. Even in the example of Tiffins I gave above, Tiffins has quite a few drinks over the $17 to make using two credits feasible. Ohana and Bon Voyage are only one credit, so there's not even a price point needed there; if you want a drink, it's covered.