Flexpay is definitely a contract, and yes they would have copies, I am sure, whether they kept them or not, though, as I have NO idea where mine is, LOL. Disney flexpay does allow you to upgrade, you have to pay the difference in full price (ie if you have seasonal pass on payment plan and are upgrading to full annual pass, and difference is say $200, you would have to pay the $200 up front for the change and your monthly payment would stay the same). I have that one too, actually. I don't believe you can put the Seaworld fun pass on the payment plan, the minimum there is the standard annual pass, but you can add extra parks midyear, it just starts your "year" over at the new rate. For example, we started with SeaWorld and Busch Gardens on ours, this summer, (year would have ended October) we opted to add a water park on, so our rate went from $13 pp to like $17 pp each month, and our year started over in July.