The break in of cables are probably limiting your success with the power generator, meaning much more improvement are likley to come as power cables and power generators are more broken in.
The clean wave function should likley improve things for 2-5 songs before in might be worth while using pushing the button again. It will influence electro-magnetism in connected components. The multi wave function has to do with how the sine wave are built up and presented. The tip of the sine wave becomes broader, meaning that more power are filled into the capacitors quicker that might improve sound (the capacitors are only filled from the upper most part of the sine wave, 50 or 60 times per second (50/60 Hz).
Some manufactures such as Gryphon build gigantic power resevoars in their amps (banks of capacitors). Usually they are less affected by the choise of power cable.