I'm using a Ranco. I really don't believe claims like that Australian manufacturer makes, power usage is directly related to the temperature differences and a controller will not change that. Using a power factor compensating controller will knock 10-20% off the usage, but not 90%.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk