N1Grammar- studying differences between similar expressions

(2016-03-24, 2:24 pm)zx573 Wrote: You can lose points for correct answers still as far as I understand (and get points for incorrect answers).

Why do you think that? The Item Response Theory stuff that the JLPT info about scaling refers you to is a pile of maths that I don't really understand, but I wouldn't expect it to result in a correct answer increasing your score or an incorrect answer decreasing it...