Posted By:
murcerfanI was sorely tempted to go after one of those 88's you mentioned, I think it was lot #15.
I think one factor to consider is that there are some deep pocket collectors who only buy PSA 8 cards, especially off e-bay, so when a pre-war PSA 8 comes around it will almost always attract bidders whom otherwise might not be in the hunt.
That PSA 8 has a lot of sales power...right or wrong.
also, Barry's auction probably does not get as much exposure as an e-bay featured listing does.
I would expect the numbers for psa vs. sgc NM 7's to be about equal, all factors considered being equal, of course.
And the PSA holder does little for the eye-appeal on N-172's, so I would't be surprised to see mid-low grade SGC cards sell for slightly more... especially if I'm bidding 
It is hard to compare numbers, because no 2 OJ's cards are identical, and most have multiple flaws to consider.