I don't see how any logical bidder would pay even close to 95% of current market value for the coins. Buyers go to auctions to buy things at discount.
Every auction I've ever observed sold its wares for prices ludicrously over their market value. I think the average buyer thinks they're going to get a bargain because it's an auction. If everyone else thinks that then bargains go out the window.
I wouldn't want to make any predictions about this auction though. It's a unique happening.
These are blocks of thousands of bitcoins. The investors are not weekend garage sale hunters on a $50 budget. They want an edge of 10 20 30% off because they have cash on hand.