Hi bzo,
The score that you earn on each section of the GMAT is a reflection of how you performed on the ENTIRE section, not of how you performed on any one question. Getting a "hard" or "very hard" question right or wrong isn't enough to define what your score will be; your performance on groups of those questions won't mean much either (not without knowing how the context of how you performed overall) . Many Test Takers become overly concerned about the implied 'level' of the questions that they face, instead of defining WHY they're getting questions wrong.
As a way to gauge what I'm talking about, I suggest that you do a full review of your last CAT. In the Quant section, how many questions did you get wrong:
1) Because of a silly/little mistake?
2) Because there was some math that you just didn't know how to do?
3) Because the question was too hard?
GMAT assassins aren't born, they're made,
Rich