I had one for 11:10 am recently. She said their last seating was at that time or 11:30. I can't remember. I changed it to 9:50 am though because a few people said that they had late breakfast ADR's and felt rushed and the food wasn't replenished.
I called today for clarification and the latest seating they will book for bfast is 11:10am, but bfast is served until 11:45am, then they begin to switch to lunch for the noon crowd.