Hey,
ich have the Canon T6i/750D with the Sigma 24mm 1.4 Art lens.
I also bought the Sigma USB Dock and tried to calibrate it.
I haven't had problems with the first three calibratable distances (0.25, 0.35, 0.6) but when I shoot at distances which are further away than those like 2, 5, 10, 20...