How much "shadow detail" am I supposed to see in a properly calibrated plasma? (Panasonic UT50)

Hey guys,

I recently calibrated my Panasonic UT50 with setting found in the forum (and played with other settings too) and I'm not sure about the shadow details, I will try to explain.
Looking at Batman The Dark Knight Blu-ray, I see scenes where different shades of dark grey/black all become one black thing and I don't see the details anymore unless I crank up the brightness higher than it should be.
For example a night scene where a man wears a dark coat with a slightly lighter shirt under the coat, the shirt and coat blend as one dark thing, as I increase the brightness I start seeing that they are not one object, but than the brightness is too high.

My questions is: Are some details not supposed to be seen because the scene is actually too dark for us to discern the details even considering that I can see the details by cranking up the brightness?

This is a question that I always had, I hope it is clear and someone can explain.
Thanks!

Black level setting is on light. I played with ranges 78 to 84, it doesn't make a big difference in term of the details, some shadow detail only becomes discernible when I crank brightness up to more than 90, but at this point I can clearly see that everything is too bright.
I just want to know if it's normal not to see all the details, because I think my settings are good.

I will check the PS3 settings(that's my Blu-ray player), but I never changed anything.

Nevermind, 78 is my contrast, brightness is at 56. Picture mode is custom.