List of gameObjects unresponsive to fast button presses

Hi Y'all,

I hope I can explain this issue clearly...here goes :)

I have 4 rows of 10 objects (hoops). Some rows move from left to right on the X axis and others vice versa.The hoops contained within each row are stored in their own individual list.

What I need is for the hoops to move by -80 units upon pressing the jump(space) button. I am using this code (inside Update) in order to achieve this :-

 //MOVE HOOPS ON Z AXIS WHEN JUMP IS PRESSED
 if (Input.GetButtonDown("Jump") && BallCollision.isGrounded == true)
 {



     foreach (GameObject hoop in hoopList)
     {


         if (hoop.transform.position.z > -85)
         {


             //MOVE GAMEOBJECT SO RESPAWN HOOPS APPEAR ON CORRECT ZPOS
             hoopsinZmove = true;

             //MOVE ROW (LIST OF HOOPS) TO CORRECT ZPOS
             iTween.MoveBy(gameObject, iTween.Hash("z", -80, "time", 0.4f, "easetype", iTween.EaseType.linear));

             //STOP HOOPS X MOVEMENT PRIOR TO APPLYING ITWEEN Z MOVEMENT
             Rigidbody thisRb = hoop.GetComponent<Rigidbody>();
             Vector3 stopxMove = new Vector3(0, 0, 0);
             thisRb.velocity = stopxMove;

             //MOVE EACH HOOP IN ROW TO CORRECT ZPOS
             iTween.MoveBy(hoop, iTween.Hash("z", -80, "time", 0.4f,
                 "easetype", iTween.EaseType.linear, "oncomplete", "HoopMoveOver"));




         }



     }

As you can see, i'm using an itween to move the hoops and to be honest this code works fine as long as there is a gap of about at least half a second between button presses.

The problem arises when I begin pressing more quickly. Most of the rows of hoops move on the Z axis as intended however one of them (different row each time) usually doesn't respond.

If anyone can shed any light on this then would be extremely grateful.

Thanks in advance :)