specially to David L Jones

[electros6]

Hi sir,
         I am a big fan of yours since the starting of eevblog. I already posted this before but I need somebody to test it since I don't have any professional equipments except scope and multimeter.
     My question is whether in commercial instruments the set value is set value is  based on the calculated value or feedback loop is used to set the DAC value. Why am I asking this because , in agilent E3631 power supply SINGLE DAC used to set 7 different values with a reference rate of 13ms , if feedback loop is used how it is possible to do refresh in 13ms.
    Why don't somebody test it please.