I have purchased an older commemmorative that was sold by this seller in the same SGS slab. The coin was several grades below what was stated but I knew at the price I paid for the coin even AU was ok. I have not been back there since. Also, I saw an article a few few weeks or a month back regarding this seller calling him/her and the grading service a fraud. I also purchased an SGS coin from another seller on ebay who I thought was reputable before I ever purchased anything from aboncom. It is graded MS70 also. I don't know if it is or not. If I can find the article I'll cut and paste it for you.
I'm sure it isn't also. Bought it from cregga on ebay. I have only been at this for about a year so when I purchased the MS70 SE about 10 months ago, I wanted to see what an MS70 coin looked like. I guess I still don't know. I paid $32.95 for it. I don't know if cregga knew or not but I do know that he had a lot of slabbed coins, mostly NGC and I was pleased with my earlier purchases from him so I took the chance. (Later bought an NGC graded PF70 SE from him.) Needly to say, I am sure that I overpaid. He told me he was an ex-US Mint manager and seemed (to my very limited experience) honest and knowledgeable about the coins he was selling. Thanks Hobo. Michael Bugeja wrote the following article regarding 'bottom-tier' grading services and specifically mentioned SGS: http://news.coinupdate.com/crossover-cross-under-or-cross-out-0382/