Thanks Alenk
The other parameters present in the balance screen, that I have reduced (Lower 1/2 Volume and Accomp. Volume) are correctly saved and recalled in various registrations, but the metronome volume is always reset to the 127 value at switch on of the piano. I don't know if the metronome volume is a parameter associated to every registration or is a global parameter, but also in this case there should be a way to store a value to avoid re-setting it again after every power on of the piano.
In the controller screen, where it is possible to set on or off the possibility to esclude recalling the various parameters, all parameters are in off state (so, all parameters are recalled).
May be somebody could try on its px 560 to chang the metronome volume and see what happens at next power on ...