Misty89 --- I don't think too many families ask for split checks at Cinderella's Royal Table, but I also don't think it's that unusual for kids to pay for some of their own food at Disney. Examples:
Suppose you have a couple teens and you choose to split up for the day, then meet up again at a certain time and place for dinner. They're going to have to eat lunch sometime, and you won't be there -- they have to pay for their own. To change the subject slightly, this is a perfect situation for the Q&C vouchers.
Then there are the kids who must-must-must-must-must have every snack they pass (despite the fact they've just had a buffet lunch with the family). I think it's perfectly reasonable to make a rule that candy and snacks come out of kids' money -- it's a way of making sure they think about whether they really want it.
Suppose you discourage soda drinking in your family, but your daughter specially wants that expensive "free refills" mug at the resort. You tell her that if she wants it, she must pay for it out of her souvenier money. Since soda is a luxury item, not a necessity, that's reasonable.
So . . . I wasn't suggesting that your teenaged daughter should pay for all her own meals -- just wondering whether you're expecting her to be "on her own" for any food expenses.
Now that you've clarified that you personally expect to spend $200 yourself on souveniers, I suppose it's reasonable to say that she'd probably spend about the same amount. I think that's a bit over the top -- that's more than my family of four spent on souveniers -- but then we don't all choose to spend in the same ways.