Initialization of prefabs

Hey, i have an issue with understanding the way that prefabs are initialized. I have two scripts, one which initializes prefabs in a for loop, and the second one is attached to each prefab and is being executed in Start method. Is it normal that the second script is being executed after the whole for loop has been executed? For example:

  // First script Update method
   private void Update() {
  for (var i = 0.5f; i < 3; i++) {
         Debug.Log('Loop' + i);
         PrefabUtility.InstantiatePrefab(tilePrefab as GameObject) as GameObject;
     } 
 }

 //Second script start method
 private void Start() {
      Debug.Log('Prefab start');
 }

Will give me output:

 Loop 0,5 
 Loop 1,5
 Loop 2,5
 Prefab start
 Prefab start
 Prefab start

instead of expected:

 Loop 0,5
 Prefab start
 Loop 1,5
 Prefab start
 Loop 2,5
 Prefab start

Is it supposed to work like that?