It also in the default setting will never let the music "clip", so if as an extreme case you set it to run it with an LUFS of let us say 8, the heavily compressed pop music might actually end up with an LUFS of 8, but the wide dynamic range classical and some jazz will only be set to the loudest it could be without clipping, so it might be an LUFS of -20 or whatever. The dBpoweramp normalizer does not include any dynamics processing so it will never decrease the dynamic range of the source, no matter how great that might be.