PlayerPrefs reset error

Not sure how else I can explain this but I have a working exp/leveling system however when I load the scene again it randomly jump to the next level and starts the exp at 0 (which happens if you gain a level). Yet sometimes it works perfectly, any ideas guys?

 public var expTillNextLevel : float;
 
 var expTexture : Texture;
 var expGainedTexture : Texture;
 var expGainedMaxTexture : Texture;
 var expBackTexture : Texture;
 
 public var expTotal : int;
 public var killsTotal : int;
 
 public var Level : int = 1;
 public var Exp : int = 1;
 
 function Awake()
 {
 
     expTillNextLevel = 100;
 //PlayerPrefs.SetInt("Exp",0);
 //PlayerPrefs.SetInt("Level",0);
 //PlayerPrefs.SetInt("Level",1);
     if (PlayerPrefs.GetInt("Exp") == 4500)
         {
             print ("Level 10");
             PlayerPrefs.SetInt("Exp", PlayerPrefs.GetInt("Exp")+0);    
             LevelUp();
         }
 }
 
 function Update () 
 {
     if (Input.GetKeyDown("r")) //Resets everything
         {
             PlayerPrefs.SetInt("Exp",0);
             PlayerPrefs.SetInt("Level",0);
             expTillNextLevel = 100;
             killsTotal = 0;
             expTotal = 0;
         }
 
     if (PlayerPrefs.GetInt("Exp") >= expTillNextLevel)
         {
             print ("Level Up");
             LevelUp();
         }
 
     if (PlayerPrefs.GetInt("Level") < 2)
         {
             PlayerPrefs.SetInt("Level",1);
         }
         
     if (PlayerPrefs.GetInt("Level") < 10)
         {    
             PlayerPrefs.SetInt("Exp", PlayerPrefs.GetInt("Exp")+1);        
             killsTotal += 1;
             expTotal += 1;
         }
         
     if (PlayerPrefs.GetInt("Level") > 10)
         {    
             PlayerPrefs.SetInt("Exp", PlayerPrefs.GetInt("Exp")+0);    
         }
 }
 
 function OnGUI()
 {
     GUI.Label (new Rect (10, 250, 1000, 20), "Level:" + PlayerPrefs.GetInt("Level"));
     GUI.Label (new Rect (10, 300, 1000, 20), "Exp:" + PlayerPrefs.GetInt("Exp"));
     GUI.Box(Rect(Screen.width/2 - 250, Screen.height - 95, 500, 30), "Current Level: " + PlayerPrefs.GetInt("Level"));
     GUI.DrawTexture(Rect(Screen.width/2 - 250, Screen.height - 35, 500, 10), expBackTexture);
     GUI.DrawTexture(Rect(Screen.width/2 - 250, Screen.height - 35, (PlayerPrefs.GetInt("Exp")*500)/expTillNextLevel, 10), expGainedTexture);
     GUI.DrawTexture(Rect(Screen.width/2 - 250, Screen.height - 35, 500, 10), expTexture);
     
     GUI.Label(Rect(Screen.width/2 - 40, Screen.height - 130, 500, 30), "Total Kills: " + killsTotal + "");
     GUI.Label(Rect(Screen.width/2 - 45, Screen.height - 115, 500, 30), "Total EXP: " + expTotal + "");
 }
 
 function LevelUp()
 {
     PlayerPrefs.SetInt("Level", PlayerPrefs.GetInt("Level")+1);    
     PlayerPrefs.SetInt("Exp",0);
     expTillNextLevel += 100;
 }

Any help will be greatly appreciated and thanks in advance.