Another option is to borrow points from the next use year to combine enough points for your reservation. i.e. If you have 100 points annually, you can borrow up to that amount from the next use year. Going forward, you can also bank one year's points into the next and that next year you would have 200 points available (100 banked and 100 current), and you could also borrow forward from the following use year giving you access to as many as 300 points at one time.
For small contracts like that, the bank and borrow option works well for an every other or every third year trip.
My guess is you will find you don't have enough points and will eventually end up adding on. We started with 230 points and were sure that would be plenty for us, but after a year we added on another 150 and then later added another 69. Now our 449 seems about right.