Someone is confusing roll center with bump steer, spindle height has nothing to do with bumpsteer.

Bumpsteer http://www.i-car.com/pdf/advantage/online/2003/090203.pdf

Roll center http://www.neohio-scca.org/comp_clinic/hand_out_reprints/Vehicle%20Dynamics2007.pdf

BTW, just about anyone can join the SAE http://www.sae.org/membership/faqs/

They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.