After you load a new init performance but BEFORE selecting Part 1 for edit if you rotate knob 1 counter clockwise you can see the value go to 0.

Before selecting Part 1 I imagine the knobs are set to common (Performance-level) assignable knobs. Not Part level. So rotating a knob at the common level doesn't necessarily affect the Part level knob unless the two are linked. What you described they shouldn't be linked.

Assuming Part 1 - you would look at Part 1's assignable knob position and this position will be the input value for the Control Assign curve.

The procedure for setting Part 1's Assign 1 would be:

1) [PERFORMANCE] (HOME) - just a sanity check to be sure you're on the home screen. Pressing this button will also de-select any Parts. On the home screen the 8 assignable knob positions are showing the Common Assignable knobs.

2) Touch Part 1. A popup menu shows up on the far left. You don't have to select anything here. You can press [EXIT] (the button) to go back to the home screen or just live with the popup in the far left. Either way - now these 8 knobs on the home screen (now that Part 1 is selected with a white box around it) will be showing Part 1's Assignable knob positions.

3) ... and after Part 1 is selected - now you can rotate Knob 1 since it will represent Part 1's Assignable Knob 1 (assuming the [ASSIGN] button is lit in the general case).

Init Normal (AWM2) defaults the Part and Common level Assignable Knobs to 64.