transform.position innacurate? [Unity 2D]

Code! :D

 #pragma strict
 #pragma downcast
 var arrow : Transform;
 var pos = new Array();
 var rotation = new Array();
 
 function Start()
  {
  pos = [-0.9, -0.3, 0.3, 0.9];
  rotation = [1, 180, 0, -1];
  var direction;
 
  for(var i = 0; i <= 16; i++)
   {
   direction = Random.Range(0, 4);
   var clone = Instantiate(arrow, Vector3(pos[direction], -2.4, 0), transform.rotation);
   clone.transform.rotation.z = rotation[direction];
   yield WaitForSeconds(1);
   }
  }

So basically, whenever I run this code, when I do Instantiate(), my arrow instantiates, but it is usually off a little bit. The thing is, it only does this when I try to change it to -0.3 and 0.3, and it can offset between -0.3 and -0.4. Hm???