I predict a big loss, based on the legal concept of "puffery". Here's the distinction - Metallic composition is a fact. Get sued for selling cu-ni as sterling silver, and prepare to write the Plaintiff a check. Grade is an opinion. Get sued for selling what Expert "A" calls VG as MS70, defend on the ground that you just "puffed" your opinion, and prepare to deposit the Plaintiff's check for your court costs (including attorney fees under the English system, but not under the American system).
That doesn't surprise me a bit. Outfits like that buy large collections, excess dealer inventory, and rejects from experienced collectors. What doesn't go to fill want lists or isn't tpg gradable, winds up in the print ads or eBay. Cleaned and often overgaraded coins are the norm, not the exception. Same experience I had with Paul Sims.