You need to de activate the front rollers and request rear only and let the front rollers free roll instead of looking for constant load when you have an uneven loading AWD system especially for just tuning purposes
The mainline can derive torque split when looking for % and fault finding but not needed for tuning
imagine a treadmill that’s a new style powered unit trying to keep up with you skipping along vs running against it your going to end up sore with bung knees quickly....
then an old style treadmill that’s literally just free rolling without any feedback or much adjustability in tension will accept your shenanigans all day long
set the rear roller to new spec and front roller to old spec and you can run at the back and skip at the front
#explainingexpertlevel9000