confused with the score conversion calculator

all gain no brain

hello guys,
i am looking at the lsat score conversion calculator that is provided on the home page of 7 sage. What is confusing me is this: when i put the number of questions that I'm allowed to get wrong in order to calculate what it takes to get the score i want, should I put the number of wrong questions on the entire 100 questions of the test or only on the 3 graded sections which make up roughly 75 questions? i ask this because if lets say I make 20 mistakes in 100 questions, but 15 in the 75 questions, I am not sure which one to put in the conversion calculator. When I put 15, I obviously get a better score, but im not sure if this number is inflated because it is assuming a lower group of questions per test then the calculator intends for me to assume.
I would appreciate your help as it would allow me to see how close to my goal I really am!

wilt

On the real thing there's 4 sections, but one is an experimental section, meaning it doesn't get counted toward your score. I would make 2 separate calculations, each with one of the repeated sections.