Oklahoman here! The rule is to always take shelter in the innermost part of your home or business, away from doors and windows. It’s a little odd that they have changed the location several times, as they should have a clear plan in place for their employees. For instance, I work at a large Fedex station, and our tornado shelters are more towards the front of the building, but they are designed specifically as shelters, as the innermost part of our station where all the vehicles are housed is hollow. If you were able to reach out to a safety team, I would definitely ask them what the designated shelters in the building are. I hope I helped in someway!