LoadLevelAdditive to load consecutive levels, levels loaded multiple times

I am trying to load some levels by mouse click(i use Cardboard SDK) using LoadLevelAdditive. The problem is that each time the next level is loaded, the previous levels are reloaded. I assigned the following script to each object in each level.

 public class Change : MonoBehaviour
 {
     int i = 0;
     GameObject target;
          //Update is called once per frame
     void Update()
     {
         //int i = Application.loadedLevel;
         LVL();
 
     }
 
     void LVL()
     {
         if (Cardboard.SDK.Triggered)
         {
             i++;    
             if (i < 6)
             {
                 string name = string.Format("SU_{0}", i);                    
                 Application.LoadLevelAdditive(name);
                 //Destroy(GetComponent(name));                       
             }    
             else
             {
                 if (i >= 6 || Application.loadedLevelName == "su_5")
                 {
                     Application.LoadLevel("su_0");
                     i = 0;
                 }
             }
             }
         }
     }