With the light level set to 0 and the secondary set to 7:
The secondary light level, meant for spawner range, completely overrides the nighttime spawn range causing it to be non-functional. You get blue Xs at level 7, but the yellow Xs that are supposed to show at level 0 don't appear.

The stranger thing is that the secondary light level uses the wrong color underground - you end up with yellow Xs at light level 7 instead of blue.

With light level set to 7 and the secondary set to 0, the underground functions properly - blue Xs at level 7 and red at level 0. But above ground, you get yellow Xs at range 7 instead of 0, and no blue Xs, meaning you still can't see the light level for night spawning.

Shouldn't it be blue Xs at light level 7 anywhere, then yellow or red at 0 when above or underground?