I ripped all my CDs including a small handful of HDCD discs without the HDCD DSP enabled but want to try reripping with that DSP setting turned on. What's the deal with the box for +6dB amplification in the HDCD window? Is it recommended to check that box, and why? Any reason one would want to leave that box unchecked?

As I understand it, the 20-bit data on the HDCD is ripped at 24-bit, but why the amplification? FWIW my OPPO player does NOT decode HDCD, but my JRiver software player may benefit by the boost in bit depth.