Does that "lower than" have anything to do with bringing the noise floor up?

I'm afraid not. The text in the dialog box is misleading.

Currently it says: "But only if the track is lower than (x) or higher than (x)", When it should actually say: "But only if the TRACK'S PEAK is lower than (x) or higher than (x)".

All it does is look at the single highest peak in the track, then add a multiplier to the whole track based on those criteria. Personally, I normalize everything unconditionally to 100 percent. Although it helps some older albums that weren't fully normalized, for the most part it does nothing because most albums are already normalized. I'd say that out of my entire CD collection, there were maybe two or three CDs that benefited from this.

Normalization doesn't usually fix the perceived-volume differences between tracks because most of those differences are due to differences in the amounts of compression in the mastering stage.

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Tony Fabris