I have a wonderful book by the white house historical association. It’s a bit dated maybe it sez “...the State Dining Room is prepared for a formal dinner of 111 guests.”
Looks like the plateau is from the Monroe administration, along with a few other items. Now, 134 guests? In the photo it looks elbows to elbows at 111. I wonder how they made more room?
State Dinner during Grover Cleveland Administration