Some test centers are roomier than others and some are more accommodating than others. I have taken one exam in a cubicle so small my elbows bumped and angered the people on either side and I had to keep my code books stacked in my lap. That center was so dark that I had to hold the code books up to the computer screen glare to see the page. All the while, there was a second room which had larger cubicles, was well lit, and had only a few people sitting in it. They refused to let me sit in that room.
I took another exam in a roomier cubicle in a well lit room. The test center proctors put me in a far corner of the room so that the noise of my pages turning would not bother anyone else. They also gave me a small side table for my books.
Two of my exams were in a third test center intermediate between the two above. The personnel and their attitude differed each time.
AHIMA does give guidelines and instructions to the test centers, but does not appear to ensure that the instructions are understood or followed. You are pretty much at the mercy of whomever happens to inspect your books and decide where you are going to sit. That is why I always make my recommendations assuming a worst case scenario.