The settings for House Code and Light Code are for the security lights you want to flash on an alarm or when the console is armed.
Actually you have two Security Light Codes. The one you set in the menu and the next highest one.
If not changed. A is the House Code and 1 is the unit code. The second Security Light Code is automatically one higher. A2
The timer function can do any of the sixteen Unit Codes for the House Code you selected in the menu. Not just the two Security ones. So you can program a Socket Rocket to lets say A3. It is not one of the Security Codes so it will not flash on an alarm, but you can still manually control it with the keypad buttons or have it in a timer.
Also you can duplicate Address so if you wanted five Socket Rockets to follow the same commands. Set all five to the same X10 address.
A Socket Rock doesn't register to the SC1200 like you would for a security device.
The SC1200 can only do one House Code as set in the setting menu.
To reprogram a Socket Rocket to a new address from its default A1.
Use the keypad buttons to send the address you want the second Socket Rocket to use.
http://kbase.x10.com/wiki/Programming_Your_Socket_Rocket_With_A_Plugin_Controller