Guys (and girls) I will upload a WIP test file of my progress of turning some interior cells to only use night time values with Sky enabled. So you can test out how it works

The meaning behind this is to create a sort of "dungeon" seperation because some interior cells doesn't have any actual "sun light" coming through any windows or holes in the ceiling. So why would that cell have day settings

Here is the file;
http://www.mediafire.com/?t38i0sz0t1kyhmnI have only applied the "dungeon" setting to one interior in this file for testing purposes.
So for testing out if it works as it should do this;
type coc AbandonedPrison01 in the in-game Console, then type set timescale to 6000 and have some intense settings for the day settings and reveresed for the night. Hopefully you won't see a change and if you do, it will hoepfully only be with a very high value of that certain setting. It worked for me atleast

The do the same for an interior without the special Dungeon Sky in it, for example I used Dragonsreach, so coc WhiterunDragonsreach and do the same with the timescale, you should see that the values changes during the day.