Goldensnow, I have been asking in other places and I got the same explanation that MDiva gave you, because I was curious also when I saw the others' score compared to mine, it seems to be that the 2 digit score is a percentile and depends on those two factors, and in the NBME form2 I got 530 which correlates according to the NBME results to 226/90 in the real test, and that was exactly what i got. So, I assume that the best NBME form to correlate with the real test is No2, at least worked for me. Anyway I am very happy with my 90 , I began to study already 1 month ago for my step2 and let's see if I can get a higher score.
Thanks for the good wishes DrJaspal19, good luck to you too..........