If you're looking at the spot on the WDW web page where it says something like "Pricing: $15-$36.99", those are not the child and adult prices for the buffet, those are merely the typical price range for that category of restaurant. A buffet with an adult price of $28.99 would fall into that category, for example.
On the other hand, if you're looking at the actual menus, those are real prices - between that and AllEars, I would guess that the higher price is probably the most recent, and most accurate. Sometimes AllEars doesn't get a menu update for a year or more, but the WDW site being its usual self, there's no guarantee that their menus are current either.