OP, you are fine as is.
Those of us in northern climes might not realize that our fuel is blended for the prevailing temps. Some of the improvement occurs at the production and wholesale level, but that is only a starting point. They only lower the gel and cloud points by a relatively few degrees. The fuel station will be doing the final treatment, usually with additives at the time of delivery, to make the fuel usable at the expected temperatures. The additives are more cost effective than lighter oils, and work just fine. Better living through chemistry and all that.
I don't have experience at -30'sF and below, and I'm sure it's different in those cases. There is only so much an additive can do compared to a blend with lighter oil. I am used to delivery-additives which make winter #2 work down to the minus teens and maybe -20F. Below that, all bets are off. :)
