The jack works i’ve tested it just on the desk yet top setup for field.
reducing volume of fertilizer though without altering drop point - is there any advantage - i guess it keeps your applied rate accurate to actual field area.
You could achieve same affect by sending a lower speed pulse to Calibrator so in the teensy if setup for 2 sections and 1 is off reduce the speed signal to calibrator by 1/2 and it will also lower the rate.