My guide explained it to me as follows:
If you add-on in the first 6 months of your use year (in the 100% banking window) they will give you that UY points, if you are past the 6 month mark, they will try to encourage you into the next year, and whatever discounts apply,
The 6 month mark is negotiable, as I got June 04 points in March 05 (9 months in).
Bill