Hi Alexander,
To model the load as a constant kW value that adds up to a desired monthly value in kWh, you would divide the monthly kWh by the number of hours in each month.
The peak value shown for each month on the Electricity Rates page is the maximum of the hourly (or subhourly) values in the month. When you use the monthly usage in kWh to adjust the size of the load, the peak kW depends on the shape of the load. If you want the peak for a given month to be a specific value, you can either adjust the monthly usage in kWh for that month to achieve the peak kW, or edit the maximum hourly (or subhourly) value for that month.
Best regards,
Paul.