You could use them all at 7 months and book where ever there were openings but not at 11 months. That is the home resort priority window and points follow that. Consider that if they didn't everyone would just buy 25 of the resort they'd like most and the remainder at the lowest cost resort.
So continuing this scenario I could only use the 50 points from the home resort to book at the 11 month window, not my entire allotment of 150 combined points?