Hi Jim,
You're absolutely correct. Different genres will certainly apply the information in different ways. For example, Electronic Dance Music (EDM) is bass-heavy so the bass boosting would be above the value determined by the equal loudness curves. A trio of jazz musicians, on the other hand, tend to be bass-light and so the bass boost (if any) would most likely be less than determined by the above set of curves.
As I said in my post, I'm only a novice. My above thoughts only deal with the concept of 'equal loudness'.
All said and done, the curves simply provide a starting place because it's easy to read approximate decibel values from a track using VU meters and then relate that information to the curves. In addition to this, PG Music provides a frequency analyser plugin with BIAB/RB that can be used to get additional useful information.
For those interested, Ozone has a feature that lets it use a sample of music in a specific genre and approximately match a particular mix's frequency responses to that sample. See the link below. It's a pdf found at iZotope. (Read the section under "Snapshots" on page 24.)
Mastering with Ozone 5 (5.2 MB, found freely available at the iZotope website)
Those interested in this thread might like to investigate the document from iZotope. Pages 15 to 28 relate to this discussion on EQ'ing
Regards,
Noel