Serge,
My experience is that one of the master volumes saves per song and the other does not (it remains a universal setting).
Knowing this I can usually get the response I want/expect. Personally I never move the master slider located between the tracks and the outputs (#1 in image below), but rather make adjustments on the Audio Out master (#2 in image below), as these do save per song. At least for me.
Hope that helps

Attached Files (Click to download or enlarge) (Only available when you are logged in)
RBMasterVoumeSave.jpg (101.2 KB, 152 downloads)

Make your sound your own!
.. I do not work here, but the benefits are still awesome