Voltage on PS Power plant make a difference?

I have a PS Audio P500 and it works ok. I recently upgraded all my ac cable to expensive but good cords. My cords are all prototype cords from the same manufacturer but never made it to production. They are not the cords you may see advertized on audiogon as the next new best power cord available. They are actually of high quality and the proof is in the listening. My last cord I changed was to a King Cobra V2 to my CDP and after a while I noticed the sound was too slow and lacked punch and "snap". While investigating the P500 on the PS Audio forum I noticed that somebody tried changing the voltage settings with positive results. As I figured I had nothing to lose I decided to up the voltage of my power plant from the 117V which is factory preset to 120V with dramatic results. I now have the punch and snap back in my system as well as the smooth sound of the King CobraV2. I was just wondering if anybody else notices a difference between varying voltage settings with power plants or other Conditioners with adjustable voltage settings. Does it make sense to have this dramatic change of sound with a 3 volt increase in voltage or is it that something else may be happening in my system? Any opinions would be appreciated.