I haven't read anything official from Harcourt, but past examinees posting on SDN says that PCAT scores are based on a testing group of all the people who took the PCAT during a certain time period (1998-2003 or something like that, I don't remember). If that is the case, then it doesn't matter on testing with you. Even if this wasn't true, Harcourt would take ALL of the people taking the October exam to make the curve. Given the large sample size, it's unlikely that there are huge differences between examination dates enough to skew your scores. So, its not like you're going to be screwed if the 50 or so test-takers in your room get 90s