Trying to lerp in different states in a switch statement

So I'm trying to smoothly lerp one of my image.fillamount to a certain decimal each state swap but seem to only get it to work on the first state but not the others. you'll notice a commented out coroutine I tried using it as a method before I tried using a coroutine and had troubles with increasing time. so if you can tell me how to increase time in a separate method that would solve my problem as well!

     public Image PowerBG;
     public Image PowerPNG;
     public Image _NulledOut;
     //public float Dampening;
 
     //private float SpeedVal;
     private float waitTime = 15f;
     private bool IsLost;
 
     //private float PrevAmount;
     private float temp;
     [Range(0,5)]
     private int FailedCount = 0;
     [HideInInspector]
     public int StreakCount = 0;
 
     public static Power instance = null;
     private void Awake()
     {
         if(instance == null)
         {
             instance = this;
         }
         else if(instance != this)
         {
             Destroy(this.gameObject);
         }
         temp = .15f;
         FailedCount = 0;
         StreakCount = 0;
         PowerPNG.fillAmount = 1f;
         StartCoroutine(HasPower(IsLost));
         Core.failed += Failure;
         Core.Success += Streak;
 
     }
 
 
     public void PowerClick()
     {
         PowerPNG.fillAmount += .1f;
     }
 
 
     IEnumerator HasPower(bool _IsLost)
     {
         //MyMono myMonoo = new Core();
        // Core myCorez = (Core)myMonoo;
 
 
         while (!_IsLost)
         {
             PowerPNG.fillAmount -= 1.0f / waitTime * Time.deltaTime;
             if(PowerPNG.fillAmount == 0.0f)
             {
                 _IsLost = true;
             }
 
 
             switch (FailedCount)
             {
                 case 0:
                     _NulledOut.gameObject.SetActive(false);
                     PowerPNG.fillAmount = Mathf.Clamp(PowerPNG.fillAmount, 0, 1f);
                     break;
                 case 1:
                     //FailState(PowerPNG, _NulledOut, temp * Time.deltaTime, 0, .2f, 1, 1);
 
                     temp += .15f * Time.deltaTime;
                     _NulledOut.fillAmount = Mathf.Lerp(0, .2f, temp);
                     _NulledOut.AlphaPingPong();
 
                     PowerPNG.fillAmount = Mathf.Clamp(PowerPNG.fillAmount, 0, 1 - _NulledOut.fillAmount);
                     
 
                     break;
 
                 case 2:
                     // FailState(PowerPNG, _NulledOut, temp * Time.deltaTime, .2f, .4f,2,2);
                     //float Ttemp = 0;
                     temp = 1f;
                     temp += .15f * Time.deltaTime;
                     _NulledOut.fillAmount = Mathf.Lerp(.2f, .4f, temp);
                     _NulledOut.AlphaPingPong();
                     PowerPNG.fillAmount = Mathf.Clamp(PowerPNG.fillAmount, 0, 1 - _NulledOut.fillAmount);
                     break;
                 case 3:
                     //temp = 0f;
                     //float TTtemp = 0;
 
                     temp += .15f * Time.deltaTime;
                     _NulledOut.fillAmount = Mathf.Lerp(.4f, .6f, temp);
                     _NulledOut.AlphaPingPong();
                     PowerPNG.fillAmount = Mathf.Clamp(PowerPNG.fillAmount, 0, 1 - _NulledOut.fillAmount);
 
                     break;
                 case 4:
                     //float TTTtemp = 0;
 
                     temp += .15f * Time.deltaTime;
                     _NulledOut.fillAmount = Mathf.Lerp(.6f, .8f, temp);
                     _NulledOut.AlphaPingPong();
                     PowerPNG.fillAmount = Mathf.Clamp(PowerPNG.fillAmount, 0, 1 - _NulledOut.fillAmount);
 
                     break;
                 default:
                     _NulledOut.fillAmount = Mathf.Lerp(.8f, 1f, temp);
 
 
                     _IsLost = true;
                     break;
             }
             yield return null;
         }
         SceneManager.LoadScene(0);
 
     }
 
     //IEnumerator FailState(Image _Power, Image _Nulled, float _Temp, float _NullStart, float _NullGoal, int _currentNum, int _state)
     //{
     //    _Temp = 0;
     //    while(_currentNum == _state)
     //    {
     //        _Temp += .15f * Time.deltaTime;
 
     //        _Nulled.fillAmount = Mathf.Lerp(_NullStart, _NullGoal, _Temp);
     //        if(_Nulled.fillAmount == _NullGoal)
     //        {
 
     //        }
     //        _Nulled.AlphaPingPong();
     //        _Power.fillAmount = Mathf.Clamp(_Power.fillAmount, 0, 1 - _Nulled.fillAmount);
     //        yield return null;
     //    }
 
     //}
     void Failure()
     {
         _NulledOut.gameObject.SetActive(true);
         FailedCount++;
         StreakCount = 0;
     }
 
     void Streak()
     {
         StreakCount++;
         if(StreakCount % 4 == 0 && FailedCount > 0)
         {
             
             FailedCount--;
             Debug.Log("reducestate");
         }
 
         Debug.Log("success");
 
     }