If you want to watch the video, I took this post from John Rafferty over on the Postwar Cards board:
https://www.facebook.com/watch/?v=5159550440808879
SGC talks about giving undefined A grades in this facebook video from today.
I watched the SGC video, and he said if you designate "Authentic Only" then they won't add the information about why the card was given an "A" designation.