Vlad - I doubt anyone will recall, as the method of measurement is not good for reaching the conclusion required.
The percentiles are not on the same pool of questions - they are weighted individually and give the answeror a rank (say UP if correct, DOWN if wrong) and eventually it pegs a level against you.
The safest measure is that GMAT is on computers for a good reason.
Besides, you are unlikely to know when you were wrong on the test. So it is arbitrary. I would aim for 100% correct, as test conditions (be it practice, or more so in reality) will get to you. Like - the verbal is properly after 1hrs essays and 70 min maths. I doubt it is when you sit and do OG, I doubt it is when you use the Prep software.