Frontal set back error

Recent research has proved that the frontal set back adjustemet must performed at first in wheel alignment adjustment and any other trial with set back error would not efective nor in vain because of uneven frontal self centering effects on both sides that has much to do with caster trails.
The adjustments are so accurate as to micrometer level and seconds angle value.
The caster trail error is observed on hill climbing up and down because the caster angle(included angle) changes according to the road inclination.
Experimental situations exist here and there if self concentrations are scattered for researching result.