Something wrong with my project

Hi, I need help with my project because something went wrong and I dont know why. I wanted one of my scripts to choose one of 2 ''paths'' i created for objects called "Tiles"

 public Transform Tile1;
     public Transform Tile2;
     public Transform Tile3;
 
 
 
 
     void Start () 
     {
         if (Random.value <= 0.5) {
             Tile1.position = new Vector3 (3, 2.136f, -4.413f);
             Tile2.position = new Vector3 (3.481f, 2.136f, -3.697f);
             Tile3.position = new Vector3 (3.979f, 2.136f, -2.976f); 
         }
 
         else
         {
             Tile1.position = new Vector3 (3.482f, 2.136f, -4.413f);
             Tile2.position = new Vector3 (2.838f, 2.136f, -3.697f);
             Tile3.position = new Vector3 (4.319f, 2.136f, -4.42f); 
         }
     }

and then replace those objects with one of three prefabs

(that script is attached to each "Tile" object)

     public GameObject myPrefab1;
     public GameObject myPrefab2;
     public GameObject myPrefab3;
 
     // Use this for initialization
     void Start () {
         if (Random.value <= 0.33) {
             Instantiate (myPrefab1, transform.position, Quaternion.identity);
         }
         else if (Random.value <= 0.33) {
             Instantiate (myPrefab2, transform.position, Quaternion.identity);
         }
         else {
             Instantiate (myPrefab3, transform.position, Quaternion.identity);
         }
     }

I wanted to make a simple generator-like thing which i can easily control. The problem is when i run my game everything works correctly except when one of those objects become myPrefab1. It appears in game but it has different coordinates than "Tile" object. I dunno what i messed up. Can anyone tell me whats wrong ? Thanks in advance. (Sorry, english isn't my native language, so it can hurt your eyes :~)