Sounds like it may be OK either way-
From what you describe, it sounds like it fits OK no matter how you adjust it. Of course, without being able to see it in person there is no way to be sure. If you have kids in carseats or boosters, it is a great idea to take them in for a free checkup. While the technicians are fitting their seats, they would be happy to check the fit of the seatbelt on you as well. Please visit the "Free Carseat Inspection" link under the top banner to find one near you.
Sorry I couldn't be more helpful, but it may well be fitting you OK as it is. Given a choice, I would tend to want it higher and closer to the center of my shoulder blade rather then closer to the arm. Less chance of it being down along the arm if I happen to lean over a bit.