I have a problem with show the level

Hello, I have a question.
I want to show the level when if game were level up.
So I wrote this script.

function Start () {

}

function Update () {

}

function OnGUI()
{

    var sw = Screen.width;

    var sh = Screen.height;

    var lev = Application.loadedLevelName;

if(Time.time>0.0 && Time.time<2.0)
{
	switch(lev)
	{
		case 'Level1' :
		GUI.Label(Rect(sw/6, sh/3, sw*2/3, sh/3),"Level1",labelStyle);
		break;
		case 'Level2' : 
		GUI.Label(Rect(sw/6, sh/3, sw*2/3, sh/3),"Level2",labelStyle);
		break;
		case 'Level3' : 
		GUI.Label(Rect(sw/6, sh/3, sw*2/3, sh/3),"Level3",labelStyle);
		break;
		case 'Level4' : 
		GUI.Label(Rect(sw/6, sh/3, sw*2/3, sh/3),"Level4",labelStyle);
		break;
		
	}
}

}

The problem is this.
When I build and run the game, Level 1 was showed. but other wasn’t.

What’s wrong? What can I do for fix this problem?

Please Help me.

Time.time the time since the game started. So unless you can get from level 1 to level 2 within 2 secs, you’ll never see the message after level 1.