Problems with 2d arrays , += incrementing values

Hi guys, i dont understand why i cant += the tempEssence and referenceAmount variable together when they are both floats. My intention is for when E is up after being pressed down, i want to add a value to a multidimesional array of size, (a x 2) a >= 1; I have initialised variables as shown. I dont know why but rather then adding to tthe location in the array it just overwrites it.

 var tempReference = new Array(selectedEntity,tempEssence);
 var tempEssence:float = 0f;
 var lifeEssenceCarrier:float = 0f;
 var entityWithinReach:boolean = false;
 var extractEssenceSpeed:float = 10f;
 var selectedEntity:String = "default";
 var selectedEntityObject:GameObject;
 var maxHealth:float = 100;
 var minHealth:float = 0;
 var objectReference = new Array();

 In the update method i have:

 f(Input.GetKeyUp(KeyCode.Q) || Input.GetKeyUp(KeyCode.E)) {
     var foundEntityInArray = false;
     tempReference[0]= selectedEntity;
     tempReference[1]= tempEssence;
     if(objectReference.length == 0) {
         objectReference.Push(tempReference);
     }
     for(i = 0; i < objectReference.length; i++) {
         for(j = 0; j < tempReference.length; j++) {
                 if(selectedEntity == objectReference[i][j]) {
                     var referenceAmount:float = objectReference[i][1];
                     objectReference[i][1] = tempEssence + referenceAmount;
                     foundEntityInArray = true;     
                 }    
             }
         }
     if(!foundEntityInArray) {
         objectReference.Push(tempReference);
     }        
     Debug.Log(objectReference[0][1]);    
 //    Debug.Log(selectedEntity == (objectReference[0][0]));
     resetTempEssence();
   } 

Specifically the middle for loop is the issue where it is not += to objectReference[i][1].

Help would be much appreciated.

Thanks a bunch