Should Underscan change the picture (beyond the size)?
 

I just picked up a used (but in very good shape) Ikegami TM9-1 for use with my PD170 and DVX100A. Plugged everything in, calibrated everything and I love it. That said, when I switch to Underscan, it seems that the contrast and/or brightness changes a bit (it gets darker/more contrasty). I'm inclined to think that it's a natural byproduct of the Underscan function, but I'm no expert. So, is this a normal change that most monitors go through between under and overscan or is it likely just a glitch due to the monitor's age?

Thanks.

~~Dave