Yes, that is true in part,… However if the Microstepping is set wrong that will also cause the calibration of movement to be off as well, and the fact that it is an exact multiple of 4 off when the grbl setting is set correct for his model cnc indicates that the microstepping is set different than factory defaults.
Sure, one could leave the microstepping settings alone and adjust the $102 value, however depending on the microstep settings that can cause issues with holding tolerances, AND if he has to perform a new machine setup in Easel, Easel will automatically re-set the $102 to factory, so he would need to remember the re-calcuated $102 and make sure to change it after a machine setup, before he runs the next carve or he’ll be right back here.
Hence the recommendation to go into the X Controller and set the microstep settings back to defaults.
I’m betting that Oliver’s microstepping is set to 1/8 across the board instead of Z being set to 1/2 as it should be. because this would cause the exact issue he is experiencing.
The Red Box of Switches here should be set differently for the Z compared to the X,Y