The system currently only allows you to make a pre-booking within the first SEVEN days of your hotel stay, and those dates will still only open up one day at a time (there is no "arrival date plus 10" system like there is with ADRs). So if you are arriving on August 28th, then on August 1st you can book for your first day, on August 2nd you can book for your second day, on August 3rd for the third day, etc., up to a maximum of seven days into your stay.