First off, I just wanted to say that I have been using your night settings HD-Master and they are excellent. I found the picture to be much sharper overall than the D-Nice settings. That could have something to do with me not following his procedure at all though.

I found something out that pertains to your
Day settings. I was recently testing some things myself, trying to get Game mode as accurate as your night settings. I noticed that contrast is actually capped on all the modes. I didn't test on Cinema or Vivid, but I did check the rest of them. On THX Bright Room, Custom, and Game, the contrast is all capped at 80. On THX Cinema the contrast is capped at 70. I didn't use any kind of equipment, but I used a number of different samples. The increase in brightness is easily noticeable going from 75-80, and 65-70, respectively. Anything farther than those points yielded absolutely no detectable change in brightness. So unless I'm way off, your day settings are only 2 contrast higher than your night settings.