Pole 8 blocks moved in by 100 microns.
This reduces the gap by 100 microns.
Pole 8 has +By.
The effect is an additional +By at pole 8.

x-slope before pole move: 2.8646e-007
x-slope after pole move: 5.2471e-005
(sign correct for +By)

Sensitivity:
reducing the gap by 100 microns changes the slope by 5.22e-5