With the current power price control, it is only possible to switch devices when the current power price is x % above or below daily average price. With aggressive price control, e.g. on only when 10% below daily average, this algorithm doesn't work when daily price variations are small. A better algorithm would be to switch a device on during the x cheapest hours of the day, and off otherwise. This algorithm would work with both, small and large daily power price variations.