kerosene will not have the lubricity of good diesel. diesel today, IMHO.. does not have the lubricity it used to after the refining process to go to ULSD.
suposedly the makers treat for winter and lubricity... but never hurts to dose with some power service.
if you have already mixed kero and diesel 1 to 1, then you should be covered for most cold weather unless a white out snow in hits. will it hurt to add power service? no. might get you some cetane , and will add some lubricity..