The only problem is one of organization. You'll need to make sure you don't miss any banking deadlines, but otherwise having multiple Use Years can really simplify the process if you can use different Use Year's for reservations at different times of the year.
We have four different Use Years and I use a checkbook program (MSMoney) to track them. I just set up each contract as an account and make deposits (annual Use Year point renewal) and write "checks" (make reservations) for each account. I enter the reservation number and any banking or cancellation numbers in the "notes" for each transaction made.
I wouldn't worry at all about having multiple Use Years.
Enjoy!