Hi
I took my step 1 June 25th , 2003 . I got a 244.
Yes, Kaplan's simulated test is VERY tough. Using Q-bank, I used to average 70-75%. But the questions provided in the simulated test were painfully difficult and I often slumped into the 50s%.
Your best indicator before your test however, will be the released items (the 150 questions ) sent to you by USMLE.org