I think you may be right. Ill try to get a picture up of a "blast white" coin they they have for sale using the same photography techniques. I have bought coins from them before and I have never sent one back even though they have a guarantee. Their coins always look better in hand than their photos. I'm still on the fence about this coin. At first I thought I might pass, but after enlarging the pictures and reading some feedback I dont think I would have buyers remorse. The dealer offers 100% money back if not satisfied. Numismedia values this 1917-S at $192. I might offer them $150 for it. If they accept I think I'll be pleased with that. If they decline Ill probably pass on the coin altogether. Sounds like a reasonable compromise with myself!
From the same vendor this coin is described as "Frosty mint bloom". I think that their photography is partially to blame for the appearence of their coins.