Posted By:
davidcyclebackMastro sold a lot of Frisch's vending boxes and I heard (rumor) that they didn't all grade well. Beyond wear, coming from vending doesn't mean perfect centering. Though vending can produce high grade cards. Since the boxes are unsealed, the rule is to buy vending from a reliable seller.
Personally, I don't think the natural curve should effect grade, but I'm not a professional grading company.