The “Pending Employment-Based Form I-485 Report,” displays the total number of pending adjustment of status applications, per preference classification. The report shows how many pending adjustment of status (green card) applications in each preference classification have priority dates in a given month and year. You can use this chart to determine how many applicants in your preference classification have priority dates in the same month and year as your own.
I think it will be different with each people. In my case, all three times were different.
The officer usually did a small talk with me while going to the room from the hall asking me about the weather and other information which was not listed in application from my previous state where I lived and how I liked it here. IMO, I took that in good and bad way. Good way in the sense, that he wanted me to feel comfortable and bad way, like as if he is saying, I already know everything about you. So, its a mixed bag.