The OAT is a pathetic excuse of an exam, the fact that the averages are around 300 and most schools consider 330 to be competitive speaks to the fact that getting into OD school is easy (because OD schools only want your tuition basically). The fact that so many people score so poorly on the exam attests to yet another fact, that OD students in general are less smart than those taking standardized tests for things like the MCAT/DAT/LSAT/etc.
If you scored 97th percentile on the MCAT, you'll score nearly perfect on the OAT exam easily.
310-330 is around 50-65th percentile, 370 is literally 90th percentile, 380+ is 96th+ percentile.