Some things to keep in mind though with the flex pay option if you decide to go that route (I did myself a few years back)...
1. You Flex Contract starts the day you purchase the pass, however your AP year does not start until your first use. That means that should you decide to buy the pass today, but don't actually go to the park until say... august 15th.... Your Flex Contract year will run from July 3rd 2013 - July 2nd 2012... but your AP will be valid from August 15th 2013-August 15 2014....[assuming you don't renew]
2. If you decide you want to cancel and not renew your flex account, you would need to make the request about 30days before your flex account year is up. This would be around June 3rd 2014 in the above example. Your AP would still be valid for the remainder of the AP year... or August 15th 2014.
3. If you don't cancel your AP, Your monthly payment will increase slightly after 12 months since the following year you will being paying the full price for the AP, however your price is locked. Basically, take your Downpayment amount, divide by 12, and add that to your existing monthly payment. This will be your monthly payment from now until whenever you decide to cancel your AP.
4. If you would prefer to take advantage of the lump sum renewal discount, you can do that too. You would need to cancel your Flex Account within the last month, and then you will need to turn around and pay the lump sum renewal discount. That will get you off the flex pay renewals and onto the traditional lump sum renewal. (You cannot go back to the flex pay system at that point).
Hope this helps!