Sansui 5000x power control

[Ric27]

On the back of my Sansui 5000X is a master power control. Very clever device if you have typical moronic teenagers in the home that might get the notion to see just how loud the old man's Hi Fi will actually get. Hence stifling there erg to destroy things just to see them or hear them destruct. But hell I was the same way so I understand. Anyway when it set up this receiver in my main system I thought I would try it in he lowest position so as to limit the power as far as the control would allow. Man that really marks me a over the hill rocker for sure I know. The amp even so limited cranks my very efficient speaker system well into the pretty damn loud specter with ease but it might not blow out the voice coils.

My question is; does that master control in any way change the power available in reserve for head room that would have effect on distortion control?

Ric