I had a 85% individual score and only a 30 program percentile rank, which I totally can't understand. I need at least 45, for my program, which seems to me that I would need a 100 percent individual score. Jeez. Good Luck on your score, your question makes sense, but I think your score is probably pretty solid.
I can't remember one question on body systems. The test asks several experiment questions, and even had a question about mountains, also several about things off of the element table, electrons and such. It is VERY random. You will probably do better than expected though, just stay positive, Good Luck!