First, that's not true. The procedure was the same, but the measurements were different by make and model as you can clearly see in the FSM excerpt I posted.
Second, radials and bias ply's perform completely different with regard to handling and load distribution. It's literally tire construction 101. The alignment settings to make each one perform properly are actually
opposite from each other.
It's not a theory, it's basic physics.
Might want to do some reading before you keep spreading that misinformation.
Basic construction and performance differences
https://www.hemmings.com/hmw/bias-ply-or-radial-tires.html
Differences and how/why they effect alignment settings
Tire Tech
Differences in how they stress rims (some rims are not safe for radial tires!!!)
https://www.sema.org/files/attachments/WTC-2011-05-Bias-vs-Radial-Tire-Wheel-Fitment.pdf
