How do I create separate instances from a class?

Well, I thought I would try to be clever and create a class for my score popup which I could instantiate at any time through a single line of code. That will save time right? Well , I use following line of code to trigger a score popup (a little +200 above the gameObject), but it seems that I can only trigger one of these at a time.(ie the first object has to finish its anim before the next object can trigger a popup) I kind of thought that the class would be newly instantiated every time an object called the TriggerPopUp method so I could have hundreds of these things at once. How can I do that?

 TriggerPopUp("+200",gameObject);

And the code for this class is here:

 #pragma strict
 import TMPro;
 
 /*
 Call this using TriggerPopUp("+200",SenderGameObject);
 
 */
 
 public static class ScorePopup extends MonoBehaviour{
 
     var targetObject : Transform; //the 3d object5 to align to
     var score :RectTransform;
     var canvasRectT : RectTransform ;
     var textMesh : TextMeshProUGUI ;
     var popUpScore :GameObject;
     
     
     var popUpExists : boolean = false;
     
 
     function Update () {
 
     }
     
      //always position the score at the parent obejct
     function PositionUI()
      {
          print("POSITIONING:");
           var screenPoint :Vector2 = RectTransformUtility.WorldToScreenPoint(Camera.main,targetObject.position);
      
          score.anchoredPosition = screenPoint - canvasRectT.sizeDelta / 2f;
          
      }
  
      //make the score visible and animate it
      function TriggerPopUp(textToDisplay : String,go:GameObject)
      {
          //print("Clicked in class");
          if(popUpExists){ return;}
         
         //create pop up score from prefab
         popUpScore = Instantiate(Resources.Load("PopUpScore") , Vector3 (0, 0, 0), Quaternion.identity);
         
         popUpScore.transform.parent = go.transform;
         popUpScore.name = popUpScore.name.Replace("(Clone)","");
 
         targetObject=go.transform;
         canvasRectT = go.transform.FindChild("PopUpScore/").gameObject.GetComponent(RectTransform);
         score = go.transform.FindChild("PopUpScore/Score Text").gameObject.GetComponent(RectTransform);
         textMesh = score.gameObject.GetComponent(TextMeshProUGUI);
 
 
         yield WaitForSeconds(0.01);
         PositionUI();
     
     
         if(popUpExists){ return;}
         //var reset =true;
         popUpExists =true;
         
         
         textMesh.text=""+textToDisplay;
         textMesh.color.a=1;
         
         score.gameObject.transform.localScale=Vector3(1,1,1);
         PositionUI();
         
         //animate
         iTween.ScaleBy(score.gameObject,iTween.Hash("x",1.5,"y",1.5,"time",0.5));        
         
         yield WaitForSeconds(0.5);
         PositionUI();
         //fade out
         while (textMesh.color.a>0 )
         {
             textMesh.color.a-=0.03;
             yield;
             
         }
         popUpExists =false;
         Destroy(popUpScore);
         
      }
 
  }

Cheers