surely it would have to be a direct ratio of the power required for each function. I.E. if the compressor is dragging 3hp, which for modern equipment is a fair bit, but just suppose it is that at lower level on a hot day and you were using max continuous of 220hp say. that would give you less than 1/60 of the normal consumption???
would one need to switch the aircon off at higher cooler temps? surely there is a little thermostat gadget that would only demand the power required to cool the difference between that selected and OAT.