Ahh, I see. Not sure if I've been calculating incorrectly, but I always thought it was 60 days from your first day and technically 65 from your last day of stay.
i.e. We're staying January 2-8. Window opens up on November 3 (60 days from January 2), but I can book reservations for January 2-8, which is technically 66 days from January 8.