Only being on the very fringe of Duo-Art technicalities, I can only
say that Bernt Damm's questions about levels merely strike me as a
stimulating contribution of the sort I would make once I started to try
and set up my own Steinway DA (currently mute), and very far from an
attack on anyone.  He makes a perfectly reasonable point in asking,
do we agree to call the 16 DA levels 0 to 15 or 1 to 16 ?  It's easy
to get confused.

My local expert is Denis Hall, whose 1914 Steinway OR and 1926-ish
G. Gaveau Duo-Art grands, after the finest of adjustments, exhibit
completely different characteristics .  He breaks his stacks open just
to change his valve clearances by 0.002".

I don't think I'm misrepresenting him by remembering him as saying, "At
the end of the process you forget the curves and listen to the music".

Dan Wilson, London