The center does not behave like the letterbox areas (which are prone to stubborn IR whether in the form of brightness differences from letterbox viewing or actual image retention), so the compensation mechanism seems to be a primary cause. The fact that I had the panel switched out in April for another (due to 4 dead subpixels) might be exacerbating this issue. No reset was done. This relates to current and voltage as it pertains to different areas of the screen. I found this explanation at AVF enlightening/intriguing: http://www.avforums.com/goto/post?id=21111002#post-21111002