My understanding is that you can make ADR's 180 days before your check in date and then up to 10 days into your reservation. So for example if you are staying for a week, you can cover the whole vacation. You can't make them 190 days prior to check in.
If you have a reservation number you can book a dining reservation at 190 days. It also works out to be the same as being able to book 10 days in advance of your 180 day period.
I am currently booking dining reservations each day at the 190 day period to ensure we get certain restaurants. like le cellier