Hi Jodi!
It can take some careful planning to get the best use of your table service credits!
I usually advise against using the two credits per person for Cinderella's Royal Table. When you divide the cost of the meal by two, it really doesn't work out to be a great value for each credit. I would suggest looking over the menus at
www.allears.net (Click on "Dining" at the top of the page and then on "The Menus" on the right) to get an approximate idea of what your meals might cost at each of the restaurants you've chosen. Then you can decide if those two credits are better spent elsewhere with CRT being an out of pocket expense.
Unfortunately, you can't split the meal by using one credit and then paying the balance out of pocket. The only option I can think of would be to split your check and have half of your party use the dining plan and the other half pay out of pocket. For example, if you have a party of four, let two people use the dining plan (4 credits) and pay out of pocket for the other two meals. You would have to make your server aware that you would like to do this before the meal and it would be at their discretion to allow this or not.
Good luck, and I wish you a magical vacation!