For example, if you are booking a trip that will take place during your June 2010 UY, your 2010 UY points will be available for a trip. However, if you are booking a trip that falls in your June 2011 UY, your points for 2010 UY would not be eligible for a trip unless you banked them, even if the 7 month mark for the call falls into the 2010 UY.
For example, you want to travel in June 2011, during your 2011 UY. 7 month window for this trip is November 2010. When you call in November 2010, your 2010 UY points can only be used for this trip if you bank them in to 2011. If not, then they will not be available for that trip.