They probably mean something along the lines of a 20% reduction in losses. Or, they're comparing at an operating point that is far from peak efficiency. Motors

They probably mean something along the lines of a 20% reduction in losses. Or, they're comparing at an operating point that is far from peak efficiency. Motors can have 70% or lower efficiency when running at low speeds. If efficiency is 90%, then 10% is waste; cut that by 20%, and your motor efficiency is now 92%. Something like that. There's a lot of ways they can arrange the math, not to mention it's not clear which motor they're comparing to, which makes this kind of claim very vague. They should just state the efficiency they get.