There is a magical equation. From what I understand is that the test has "easy" questions and "hard" questions and "study" questions. You get more points for answering harder questions right and no points for the "study" questions. I believe every section has the 5 study questions... the ATI book explains why they do that, but they don't count against you or anything.
When you are done with the exam your score is called an Adjusted Individual Score (AIS) which does all the math for you for the easy and hard questions you got right or wrong.
Does that make sense?