Yes, I think you are right. Thank you for confirming. I re-read the manual again, very slowly, after your prompting. I had mis-over-estimated the instruction in the Setup section of

To store the settings
Once you have adjusted the frequency response for the speakers in your system you should store the settings using the following procedure:
Press Function Store.

which of course is referring only to the frequency response in Free/Boundary etc, rather than Bass and Treble, even though Bass and Treble come up as you cycle through the available settings in Setup mode.

Thanks again.