If I understand how the electric portion of the thermostat works it isn't actually electrically moving the stat. It is a heater element that is capable of working the wax in the stat when the computer decides it wants it - much faster than the wax on its own. Basically if the ECU detects extra load it can start the process before the hot coolant would even get to the wax in the stat.
From the service manual
"An electrically assisted diaphragm-type thermostat controls the operating temperature of the engine by controlling the amount of coolant flow to the radiator. The thermostat is located inside of the thermostat housing. On all engines the thermostat begins to open at approximately 88°C (190°F) to allow flow to the radiator. The thermostat is fully open by approximately 100â?°C (212â?°F). An electrically assisted thermostat provides broader and faster operation than traditional thermostats, In addition to the mechanical function of the wax sensing element, electrically assisted thermostats incorporate an electric heater within the sensing element. This heater is controlled by the PCM, which receives information on the speed and load conditions of the engine. It uses this information to regulate the temperature of the coolant. Mapped data (lookup table) is stored within the PCM to govern when and how heat is added to ensure optimum engine performance.
In standard operation, an electrically assisted thermostat functions in the same manner as a conventional thermostat only at a higher engine temperature. coolant flows around the wax of the thermal expansion sensing element. As the temperature rises, the expansion material melts, increasing in size and moving a piston, which in turn increases the flow volume of the coolant. If the temperature drops, a spring pushes the piston back to its starting position, reducing the flow rate of the coolant or closing the coolant circuit altogether. When under a sudden, heavy load, an additional heat source comes into play with the map-controlled thermostat. Once the conditions of the stored operating map have been fulfilled, a heating element integrated in the expansion material is enabled by the engine management system. This additional heat source allows the wax to expand quicker, opening the thermostat fully regardless of actual coolant temperature, so the coolant flow is increased, immediately allowing the engine to operate within the Yeah, optimum temperature range without danger of overheating."
