I would not trust that method on lug nuts. Most likely, it will be way under when dealing with lug nuts. Most American passenger cars torque from 87-155 ft-lbs, depending on brand, Asian imports range from 76 (Toyota), 80 (Honda and Hyundai) and '87 (most others). Full size trucks get into some rather high torque specs, GM trucks run at 140, Dodge is 135, and fords run at 150. Those are specs for 1/2 tons, 3/4 and 1 tons get even higher, with some fords getting into the 220 ft-lbs range.
I'll agree with the method described for covers and non-essential parts where exact torque doesn't matter much, but on rotating assemblies and brake/chassis components, torquing to factory specs is the safest way to go.
