The requirement is to monitor an energy meter that gives 1000 pulses per KWH.
Once you click on the calculator, you can enter the scaling, the top four boxes are the only ones of interest:
You can see I've entered 0 to 1000 pulses (or counts) in = 0 to 1 (KWH)
Z and X are fixed at 65535 and 0 respectively.
So the calculator calculates the engineering range for you in the green boxes as 0 to 65.535 (KWH)
This is entered in the input set up screen, remembering to add KWH as the units: