I know this topic has been beaten to death but I'm still not sure I understand it completely. I'm going to use round numbers for simplicity's sake, and I also understand that they may stop sales of the Magic Key passes at any time. So my scenario is I buy a 4-day hopper for $500 and use two days of it which are days that are blocked out for the enchant pass (Feb 17&18). On day 3 (Feb 19) I decide to upgrade this pass to the enchant key which costs $1000 (again round numbers for simplicity.) I can apply the whole $500 which leaves me $500 to pay, correct? Also, the anniversary date of the pass would be the 3rd day (Feb 19)? I did use the search function, but I didn't find an answer that completely satisfied me.