Although ballast fuel is part of the fuel load of the aircraft it is being carried for a specific purpose, that being to avoid the need to load ballast bags or blocks. Although it could be used in an emergency situation it would be at the risk of compromising the trim of the aircraft.
For loadsheet purposes it should be shown as a service weight adjustment( or whatever term your company uses) as part of the dry operating weight calculation and so form part of the zero fuel weight. The fuel entry for loadsheet purposes is fuel on board - ballast fuel - taxi fuel.
This, I was taught, is the correct procedure and the one I have used for many a long year. In fact back to the days of the BOAC Super VC10.