Bastlr! WOW perfect, MANY THANKS!
this confirms what I had suspected that the DAV 46E has no chopper opamp, it is just a reference and KV divider.
After realizing the polarités and 1V 10V switches were scratchy, I just used contact lube and the 10V was stable, I could calibrate with the Keysight 34465a to 10.0000
Running an overnight stability trend now.
Enjoy,
Jon