Ultimately, it's your decision. The math might work in your favor to buy a VB or AUL contract to use at WDW, but I would suggest that you seriously consider how you will feel when you cannot find availability. Once you wait until the 7 month mark, if nothing is available, what will you do? Your use year will come into play because the longer you have to wait to find something, the closer you could be coming to your banking deadline. This is not to say that buying "off-site" to use at WDW won't work, but (especially in the case of AUL) it may not work ALL of the time over the length of the contract. Make sure that you will have a backup plan that you are OK with if you cannot get a 7-month reservation. When you buy at WDW, that backup plan is usually to stay at your home resort. If you buy at Aulani, you may find yourself going to Hawaii a lot!