Maybe it is grain dependent? I checked the Crisp Brown Malt and Canada Pale Malt.Every single one under Ingredients -> Grain Malts -> Grain Sacks says the same thing for me. Very strange. Maybe time for you to stock up.
Yeah, I see that too. But when I go Ingredients -> Grain Malts -> Base Malts, pick one, then pick 55lbs of it, it doesn't say +ship and doesn't calculate out that way in my cart. Try it, see if it works for you.
Now that I've double checked, it is only the Canada Pale Malt that gives me $7.99, and I notice that isn't listed in the Grain Sacks list.
Either way, I get good enough deals locally, either from Larry's Homebrew or if a brewer orders it for me. I plan to check out Brew Brothers next time I'm in Portland though.