Thankful for this thread, worked my way through it this weekend, and it solved an annoying problem. During the past couple of months, I started noticing picture had become washed out. And I literally mean had become, because I am pretty sure this was all correct when the calibrated projector was installed a couple of years back, because I was so happy with the black levels.
After reading the thread I double checked range settings, and found both madvr and the nvidia driver to limited level range 16-255. Now madvr is set to 0-255 (as per recommendations in this thread) and nvidia 16-255, and black levels came back to what I remember as good and normal.
Problem is solved, but the question remains - did the washed out thing happen because of range default change in some recent madvr update, nvidia driver update, both, or was it always this way?