From memory its just a staffed window that checks your paperwork and i can never remember there not being a queue of farangs seated waiting their turn . I have to say that Korat IO is imo somewhat confusing to say the least in respect of the correct queue to join but the helpful girls will soon point you to your correct queue BUT i can see problems when you try to jump the queue at your allotted appointment time, hopefully the girls will be managing the issue.
We will see lol