I actually took a kaplan course before my mcat and took around 7 of their full lengths, in addition to all of the AAMCs. For me, my kaplan practice averages were spot on with my actual score. The thing with kaplan is that, they make the questions very difficult and then give you a generous curve, whereas the AAMCs are easier with a stricter curve. To be honest, the actual mcat I took was more similar to my kaplan practice tests.