Let's see if I remember this right. Kerosene can be added to the regular Sthil bar oil to thin it out.
I mix the two grades Sthil grades together for cold weather cutting but I don't do much work in sub zero degree weather . Zero and above yes.
Personally, I think the winter grade Sthil oil is a little to thin for my taste. The consistency and flow from the bottle from mixing the two oils is about right to me for cold weather work. The oil tank is also picking up heat from the engine which is another reason why I don't use the winter grade straight from the jug. .
I use the ole' walmart oil, summer and winter. in the winter time i keep the jug in the front of the truck to keep it warm. seems as though they may have changed thier formula because it doesnt seem to get as thick this yr as it has in yrs past.
Just thin the oil down with kerosene, be careful using motor oil. This will be flung off the bar and not do what bar oil does, it doesn't have the sticky agents in it. Remember bar oil cleans, cools, and lubes.