RBM used improper if not deplorable usenet message composition style by
full-quoting:

This is a commercial service and metering equipment. How is he
going to guestimate demand?

Demand (or load) doesn't have to be guestimated.

There are a fixed set of lights, appliances and devices in this office,
as well as a relatively fixed schedule of use for them. We have a basic
week-day and week-end pattern, and for the week-days we have diurnal
(day - night) pattern of usage. Since the average month has 730 hours,
comprised of 4.34 weeks, we know that there will be 209 "week-end" hours
and 521 "week-day" hours. The week-day hours can be further decomposed
as 217 "day-time, week-day" hours and 304 "night-time, week-day" hours.

So we have 3 different loading conditions where the energy consumption
during each condition is assumed to be constant: Week-day day-time,
week-day night-time, and week-ends. If a current measurment is
performed once for each of the 3 conditions, and then extrapolated over
their projected duration over the course of a month (217, 304 and 209
hours respectively) then if the three total are summed the result should
approximate what the billing meter should measure if that same exact
device and appliance usage pattern is replicated during a typical month.

The exact hours of each loading condition can be exactly specified to
match a given utility bill if the meter-reading dates are known for the
bill in question (that will tell us how many week-end and week-days
actually occurred during the billing month of interest).

Based on 5 years of previous bills, about 75% of the monthly meter
readings are between 1750 and 2250 kwh. Very few go higher than 3000,
and only 2 have ever gone above 4000.