Turret aimming is off.

I am having an issue with aiming of my turret. The turret seems to be aiming and shooting right above the cube (enemy). I believe the problem is somewhere in this code.

function CalculateAimPosition(targetPos : Vector3){
    
    var aimPoint = Vector3(targetPos.x-transform.position.x+aimError, targetPos.y-transform.position.y+aimError, targetPos.z-transform.position.z+aimError);
    
    desiredRotation = Quaternion.LookRotation(aimPoint);
    
    }

I tried using Quaternion.LookAt(pos) but the turret would rotate incorrectly. I give up trying to figure this out, if anyone has ideas please let me know. I just want it to shoot and hit that darn cubeā€¦ . . . .

Here is my turret code if you see something else that can be changed

  var myProjectile : GameObject;
    var reloadTime : float = 1f;
    var turnSpeed : float = 5f;
    var firePauseTime : float = .25f;
    var muzzleEffect : GameObject;
    var errorAmount : float = .001;
    var myTarget : Transform;
    var muzzlePositions : Transform[];
    var turretBall : Transform;
    
    private var nextFireTime : float;
    private var nextMoveTime : float;
    private var desiredRotation : Quaternion;
    private var aimError : float;

     
     
    function Start ()
    {
  
    }
    function Update ()
    {
    if(myTarget)
    {
    if(Time.time >= nextMoveTime)
    {
    CalculateAimPosition(myTarget.position-transform.position);
    turretBall.rotation = Quaternion.Lerp(turretBall.rotation, desiredRotation, Time.deltaTime*turnSpeed);
     
    }
     
    if(Time.time >= nextFireTime)
    {
    FireProjectile();
     
    }
    }
    }
     
    function OnTriggerEnter(other : Collider)
    {
    if(other.gameObject.tag == "Enemy")
    {
    nextFireTime = Time.time+(reloadTime*.5);
    myTarget = other.gameObject.transform;
    }
    }
     
    function OnTriggerExit(other : Collider)
    {
    if(other.gameObject.transform == myTarget)
    {
    myTarget = null;
    }
    }
     
  	function CalculateAimPosition(targetPos : Vector3)
	{

	
    var aimPoint = Vector3(targetPos.x-transform.position.x+aimError, targetPos.y-transform.position.y+aimError, targetPos.z-transform.position.z+aimError);
    desiredRotation = Quaternion.LookAt(aimPoint);
}


     
    function CalculateAimError()
    {
    aimError= Random.Range(-errorAmount, errorAmount);
    }
    function FireProjectile(){
     
    audio.Play();
    nextFireTime = Time.time+reloadTime;
    nextMoveTime = Time.time+firePauseTime;
    CalculateAimError();
     
    for(theMuzzlePos in muzzlePositions)
    {
    
    //Instantiate(myProjectile, theMuzzlePos.position, theMuzzlePos.rotation);
 	//Instantiate(muzzleEffect, theMuzzlePos.position, theMuzzlePos.rotation);
    var go = Instantiate(myProjectile, theMuzzlePos.position, theMuzzlePos.rotation);
    go.rigidbody.AddRelativeForce(Vector3.forward * 20000);
    }
    }

I agree with @hexagonius. You are subtracting out transform.position twice. Once on line 28, and a second time on line 62. You can change either to one. Typically a turret rotates but does not elevate. Your code does both. Since you are assigning the rotation directly, rather than than Lerping() to the angle, you could simplify your code by using Transform.LookAt(). Then you would not need to subtract out the transform.position.