I really dislike that they use the term “Turbo Lag” in there website write up. Most of the from stop lag/delay, is because of an intentional programming by Ford. All modern Fords have electronic throttles, as in your right foot pushes a pedal which tells a computer to do stuff. There is delay there intentionally to help maintain traction and give a smooth takeoff. Some vehicles have a sport setting that decreases that. Ours do not.
Pedal Max, and other devices like that remove/decrease that electronic delay. JMS actually gives you an adjustment knob so you can vary/tune how aggressive the throttle is.
Basically it demands action from the computer quicker, so you are in boost faster, but without increasing boost and power. Just takes the delay out.