Adding the kero stops it from smoking on very cold start ups and reduces the possibility of wax forming in the tank, filter and lines that causes all sorts of dramas just when the heater is needed yet seem to vanish when you try to duplicate the problem in the middle of the day to the service guy.
As far as pumping directly from the tank, always new clean fuel and mixed to the climate the equipment is likely to be used in. The diesel fuel you buy in Jindabyne mid winter is not the same blend as the diesel you will buy in Darwin mid summer, the fuel from Jindabyne will still work in Darwin but the economy would suffer but the fuel from Darwin would cause serious problems in a Jindabyne winter without fuel tank heaters and a continuous fuel circulation system running 24/7.
Once sent a crane mid summer from the factory in the Liverpool area (NSW) to China with a full tank of fuel, took them 3 days with heaters under and in the tank to get it warn enough to melt the wax and pump it out, we never made that mistake again
