I'm not sure there's a way within Windows itself to determine that. Typically what you see on the "Display Properties/Screensaver" screen is what Windows knows or has control of - as far as I know.
What you could do is write your application to be the only thing that fires up on the system for a screen saver. Basically, write your app as a proper screen saver. Your app runs, interprets the command parms, and then shells to the screen saver within your configuration. Then, start a timer within your app and then shut down the computer when the timer hits the level involved.
I could help from there, if it is necessary. But I don't think there's a setting that indicates that.
HKCU/Control Panel/Desktop is where you should find these settings.