Is the knob on your InterLink-X, stiffer than your other controllers?
Is it smooth or does it feel like its binding?
You didn't mention if your Pinching or Thumbing.
Which finger are you trying to rotate it with?
The knob on my InterLink Elite has loosened up over time.
Its the older style, with the knob on the Top.
I did swap the locations, of the 6 Knob and 7 switch, for a while.
But later put them back. I prefer it that way.
When I had the rotary switch out, I didn't notice any adjustment.
Back when my InterLink was new, and the Knob was stiff(er), I found, using a Rubber Finger Protector, gave me the traction on the knob, to work it easily with one finger.
Over time, the Knob has loosened up enough, I don't need the extra traction any more.