I booked the 4/3 deal. If I were to upgrade my 7 day tickets once I got to the World, would I only be charged the difference between 7 and 10 days? Or do you think they would charge me from four since that is all I have paid for? I'm thinking about adding the no expiration option, and then upgrade to a 10 day to use for the next trip. Any thoughts? Since you people are the experts!