I have read the manual several times in this section but don't understand. It reads:“Power Sagging models the interaction between the guitar signal and the distortion stage. Increase the amount of “Power Sagging” to emphasize the velocity and energy of crunch sounds." it also reads: "Power sagging is a phenomenon that occurs when the tubes draw a lot of electric power at high distortion rates, thereby weakening the supply voltage. Under such load, the tubes will change their distortion characteristics and sort of shut down; then as soon as the load lessens, the tubes catch their breath again" That part makes sense but seems redundant with the first statement. In a real amp increasing the amount of sag makes things kind of fold in and then open up. It doesn't create more velocity and energy. Ive noticed the manual and the videos give very different angles on controls. Read the manual section on "Clarity" then watch the video for the amp section. I have read the manual pretty well but realize I should watch the videos as I think they explain things better.
EDIT: watched the amp section video and understood differently than was written in the manual. Power sagging makes sense the way it is described in the video. I don't get why the manual states it increases the velocity and energy. As you turn the control up it decreases the dynamic gap between soft and hard playing not like a real amp does but sort of with more control.