This question about Electricity Tariff Structures please solve it.

Example (2): A production facility has four large machines with a demand of 200kW each. The machines could be controlled by a computer which would limit the total demand to 400kW at any one time. This company limits the use of machines by operational policy which states that no more than two machines should be turned on at any given time. This room is separately metered from the rest of the facility, and other loads are very minor. One morning at 8:00 am, a new employee turned on the two idle machines. At 8:30 am the plant foreman noticed that too many machines were running and quickly shut down the extra two machines. What did this mistake cost the facility? The rate structure is given as