OK Andy, curiosity got the better of me so I called them. I started with their Brooklyn location and they could not answer my question there so she transferred me to their office who could not answer either. I then tried their Great Neck location and got someone who knew about the process although I am not sure he really knew what he was talking about.
I mentioned what you posted here and said that we have always heard you should rest meat after it comes off the heat. His response was "I am not sure what you mean by resting" so that made me wonder about him in the first place. He then told me that when the meat comes out of the broiler it is not cooked. It is just seared. he then said something else that made me wonder about him. He said it was seared so the juices are locked in. Well then he contradicted himself and continued on to say that when they are sliced the juices mix with the butter and the steak is then finished under the broiler while it cooks in its own juice and butter combo.
I find it a very odd way to do it, but then again I have never eaten there so I would certainly be wiling to try it and reserve my opinions until after I ate.