Actually no, they don't count the water parks as days. So it would be the original price paid, divided by the number of park days. Take that amount and multiply it by the number of days left and that is how much you will have toward your AP. With a world hopper, you won't have a whole lot to use toward your new pass, especially considering
.... if your ticket includes water parks, it can only be applied to a Premium Annual Pass that includes water parks. Sorry! You will likely be better off using your old ticket "as is"!