Unless a measure can be shown to reduce peak demand when it actually occurs, it will really only save on kWh costs. In many parts of the country, the cost of peak demand approaches half the total electric bill, so failing to cut it means that reducing kWh by 20% may cut the total electric bill by only 10%. Many building management control systems control run times and motor speeds, but do little when all systems are running at maximum output — which is when that monthly peak demand actually occurs.
Since that vendor is charging the same for power saved on or off-peak, the value (in $/kWh) for the saved off-peak power is now higher than it would have been under the old utility tariff.