Both calling and the online system activates at the exact ninety day mark and after that date; not a range, like a couple of days before.
The online system, you have to retrieve your room reservation to activate the 90 day mark; then it will allow you to book ten days after your check-in date.
What is great about the online system is it starts an hour earlier than the call-in system. And it can readily offer sugggestions all at once, that a call-in system cannot do. I prefer the online system.
You need to have your confirmation number for each dining reservation to retrieve it. At the end of the booking, it willl prompt you to enter an e-mail to send the reservation to with the confirmation numbers. You must have the number when you check in at each restaurant.
If you don't, it will cost you a call to have them look up your reservations and give you each number.