Somewhere between 0 and 6480 kWh per day?
In all seriousness, your question mixes too many different units and concepts to make sense of what you are really asking. kWh is a unit of power consumption that will depend on how the restaurant is used and cannot be answered with the information given. If your 270kW is the actual calculated demand, it is used to size the electrical equipment and doesn't directly relate to energy use. Finally, the optional method in 220.88 provides an optional way to perform the load calculation but needs the total connected load (which you haven't given us) rather than the calculated demand load. It is another way to calculate that demand load.