If you check out Barron's Guide to Medical & Dental Schools, some schools put far more emphasis on PAT than others but in general, I don't think it's much a factor.
If you want to do really good on PAT, just do the practice problems (3-4 different sets of problems) and follow the instructions/strategies on how to do well in your book. You should be fine. I did that and scored 22 (96.8 Percentile). It works.