Kerosene = #1 Fuel Oil = Lighter and less lubricity than #2 (burns cleaner/drier than #2) = slightly less BTU (135,000 BTU per gallon) than #2
Diesel Fuel = #2 Fuel Oil (w/o DOT dye) = same fuel as home heating oil = 139,000 BTU per gallon
Winter Diesel = Mix of #1 Fuel Oil (20%) + #2 Fuel Oil (80%) = in effect what you are creating by adding Kerosene to your diesel fuel tank
Given that Kerosene (#1 Fuel Oil) has less lubricity than normal diesel (#2 Fuel oil), your memory of your engine running smoother might be a placebo effect.
With all of the diesel fuel additives on the market that address both fuel gelling and lubricity, it is unclear to me why you would want to use this old farmer's trick for their tractors on a truck you paid north of $50K for...
I run Stanadyne Performance and Lubricity formulas year round every tankful.