I’ve just reviewed some of those manuals and can find no mention of this so I’m just going by memory here….
I seem to recall that these modellers had a ring of small LEDs encircling the knob. As you physically rotated the knob these lights would track the movement to indicate the associated parameter value, min to max. Of course when you saved a preset the parameter values are stored. When you recalled the preset the LEDs showed the stored parameter values, ignoring the physical knob position. Of course, physically moving the knob engaged the LED tracking again but the stored value remained unless you saved the preset.