Copy the Game_Switches one instead of the Game_Variables one. Change the name of course, use the same stuff for Scene_Title as mentioned by S S Muu, just swap '$meph_variables' with '$meph_switches' and make sure the class name match with the actual class. Now, make sure you use the following code to set switches:
And the likes. Also note that these switches will not save to the save file, nor load for that matter.
To fix this, go into Scene_Save, right after this line:
Marshal.dump($game_player, file)
add:
Marshal.dump($meph_switches, file)
Now go to Scene_Load. Right after this line:
$game_player = Marshal.load(file)
add:
$meph_switches = Marshal.load(file)
Hope this helps.