@Emkay1001: Right, it is the console lock timeout, which is separate from the regular video idle timeout. The "Turn off the display" setting in the Power control panel allows you to adjust the video idle timeout, but the timeout when on the lock screen (which defaults to 1 minute) is not adjustable via the GUI.
You don't need to add any special registry hacks to adjust the lock screen display timeout, though. You can do it via an elevated command prompt using the following commands:
powercfg /setacvalueindex SCHEME_CURRENT SUB_VIDEO VIDEOCONLOCK <time in seconds>
powercfg /setactive SCHEME_CURRENT
This would set the console lock timeout for when the system is on AC power. To change it for the battery power profile (I wouldn't recommend this), use "/setdcvalueindex" instead.