I personally have never heard such a thing.
The calipers are bolted via brackets to the forks (or directly to the lower shock body). The forks are aligned precisely 90 degrees parallel to the front axle, which in turn presents a 90 degree alignment with the rotors as they are positioned within the calipers.
Purpose of setting the axle in the forks by bouncing the front end, with the pinch bolts loosened, is to insure that any slight "twist" in the forks as they relate to each other is minimized, and the forks are aligned and are ready to be finally tightened down on the axle's clamping surface with the pinch bolts.
You have no idea if there was a slight twist in your forks when you installed your Superbrace. Which would maintain that twist. Though I'm sure that there was not. Myself, I loosened the pinch bolts and gently bounced the front end to enable myself to sleep better at night, before installing my Superbrace.