I have listened at very high levels. Hovering ~100db. That is as loud as I care to listen, my system will do that all day,,,,I like overkill. But, as I age I prefer music that has a large dynamic range, so it peaks at ~100db. There is no set rule, but having said that, a good db meter will tell you (no matter what room) that its overloaded, your ears should tell you first.
To answer your question: yes I agree that every piece of music has a "proper" listening level. I'll only add "determined by you".
Regards,
barts