I am planning to book an 8 day vacation at the 11 month window. Is it correct that I can only book a maximum of 7 days? If so, when can I call to add on the 8th day? Can I call the next day to modify the reservation to include the 8th day which is now +7 days, or do I have to wait until the 11 month point from the added day? Do people call day by day to add on days 8, 9, 10 etc?