Right you are with the sums and the "reduced contrast in shadows".
Thanks for the reply and the chapter from your book. Very comprehensive treatment and quite generous of you to share with us all.
I guess you were suggesting that pre-exposure is valid for users of graded paper who do not tailor each negative to their paper with development methods and controls, i.e., for roll film users who can use pre-exposure to decrease overall contrast of a particular negative since graded papers now have a rather limited contrast range.
For a graded paper and a VC paper set to the same contrast (assuming for sake of comparison that the curves are the same too), however, I still can't see how a print of a pre-exposed negative will be different on the VC than on the graded paper... Both should exhibit the same response.
Usually, for me, I prefer to sacrifice highlight separation rather than shadow separation, and place and develop accordingly. However, your comments about lens flare in older photographs has got me thinking. I may try some pre-exposure to lift the shadows a bit in some scenes and see how I like it.
Of course, there's always the burning and dodging dance that we all do when we want maximum local contrast and the neg is just a bit too long for the paper.