Sony KDL-40Z "Info Banner"?

I recently bought a Sony KDL-40Z LCD TV and there is one item that is displayed on the on screen info banner that I can not figure out. On the lower right side of the banner it has "time remaining" followed by minutes and seconds. The time does not seem to count down, but it does change occasional, either up or down. It is not related to the sleep timer, I have not used that at all and I would expect it to steadily count down. Any clues as to what it is?