Yep I have.!!. . . . . . I think it's because the pulley diameters are not exactly to spec and therefore the ratio is different. Thats why I ALWAYS use the Mach wizzard because it works of the actual movement travelled and doesn't relay on calculated specs based on unknown specs of inacurate components like pulleys.!

So long as you measure the distance traveled accurately, preferably over the longist distance possibly then it works perfect.

Either that or the screws pitch are not exactly what they say they are.!!!. . . .(Very very unlikely)