Jog is off calibration

Just set up my machine with gsender 1.4.11. Running mac os and grbl hal.
Did a calibration on the x axis. Going ±100mm. It’s perfectly calibrated. When I use the jog buttons with my mouse, the movement is off. It’s of by 3mm/100mm, so with “normal” I move 5mm each click, and hit 97mm actual movement with 100mm on the DRO.
So what is going on? I have enough torque on the motors, all signals going throu ferrites. Is it som kind of ramp up ramp down issue? I have DM542T drivers on 1600steps and 4mm ballscrews.
Any thoughts?