I don't know the answer, just my personal experience with a trip in a week and a half and a trip in September. When I first started looking for ADR's for May trip I could only book the Plaza up till 3:00. Later as I hit the 180 mark for September I saw you could get dinner reservations there. I went back and looked at May and was able to push the 3:00 back to 4:15. They had later on other days that did not fit but I was happy to get the 4:15. It looks like they are back open for all hours reservations. Our only walk ups have been later in the day and we were not always able to get in.