We were told that we can get the 13 month renewal on a 13 month pass. You can renew up to 60 days prior to expiration. Verified this on the website.
Of course, it's all in the timing of your renewal.
https://disneyvacationclub.disney.go.com/discounts-perks-offers/ticket-tour/passes/
Renew Your Pass – and Enjoy an Extra Month
When you renew your annual pass by October 1, 2017 (and before it expires), you'll get a 13-month pass! That gives you an extra month to experience the magic of Walt Disney World Resort.
Remember, you can renew up to 60 days in advance of the expiration date on your pass. Here's how you can renew:
- By Phone: Call Member Services at (800) 800-9800† or (407) 566-3800†
- In Person: Visit a Guest Relations location at any Walt Disney World Theme Park or at Disney Springs to renew your annual pass.
Not valid on water park passes. Valid only on pass renewals made now through October 1, 2017. Passes are 13 consecutive months, non-transferable and non-refundable. Block-out dates apply on certain pass types. Certain events / activities are separately priced.