I've read to treat Bio differently than Dino. As in, definately run cold weather additive or cut your bio blends a little thinner i.e. go from B100 to B50 etc, in cold weather. I only run B20 about every other tank and use the white/winter bottle of Power Service with no problems so far. Haven't even changed my filters.
I emailed my B10 supplier and he replied they treat their bio w/ antigel good to 0 deg.F and I also do 3 0z/gal PS just to be on the safe side.
EDIT I just went and checked, I do @ 1 oz/gal, I fill up around 1/2 tank usually and add 1/3 of the small bottle( 32 oz bottle) so that would be around 1 oz/gal. but at 1/2 tank it prob. ends up being more than 1 oz/gal actually in the tank I would guess. And no gelling problems yet w/B10