Been a while since I messed with this. So maybe I have forgotten something.

I am using the Performance “Lay Me Down To Sleep.” My 4th voice selection is Piano Back. I tweaked Piano Back in Voice mode to lower the volume of the string sound (dialed my Tone knob Assign 2 down to -45).

I go back into Performance mode and I switching out the Pre Voice to my User Voice that I tweaked, but the XS is still playing the string volume at the old default level in the Pre voice.
What am I doing wrong? Why aren’t my voice tweaks that I made for my User Bank not being used even though the Performance is showing that the User voice is being used?

Your adjustment using Tone Knob 2 won’t affect a Preset voice when
you return to Voice mode. You must store your “tweaked” voiced to a User voice location, then go to the Peromance and replace the preset
voice in the Performance with the newly stored user voice.

I did that.  I reconfigured my Voice, saved it. Opened up the Performance and navigated to my User Bank to the saved voice.

Then, are you still experiencing the problem? I’m not clear what you did. If you wanted to lower the volume level of the voice itself, you do that in Common Edit for the voice and change it
there, or if you want to change the level of an element within
a voice, you simply set the level of the element to where you want it in the “amp” section.

But regardless, if you’re in Performance mode, then the level of a voice assigned to a part is simply a matter of setting it between 0 and 127.

Personnaly I don’t rule out that there is a bug in the voice “Piano Back”. I remember I had a problem with that voice: I recorded something with it (with the Piano definitly louder than strings) and when I played back I only heard the strings. I don’t exactly remember what I did then, I think I tweaked the recording again (with Assign knob to make piano louder), stored and then the problem was gone.

Kevland1, I think what you did was good, but perhaps it doesn’t work with this particular voice, with all the others it does. Advice: tweak “Piano Back” in Performance mode and accept a possible bug in this voice.

Marcel