Smooth the Changes in TimeScale, in TimeBending script

Hello, I made this JavaScript for an effect much like need for speed most wanted, where you could slowdown time to make difficult corners by pressing a key.

Two Questions: 1. Is this hard on an iOS Device (its processor consumption) 2. How do i apply a Lerp or Slerp to the time changes?

Code:

 #pragma strict
 var bendTimeDown : boolean = false;
 var bendTimeUp : boolean = false;
 var BendTimeUpCompleted : boolean = false;
 var count : float = 0;
 
 
 
 
 function Update(){
 BendTimeTrigger ();
 BendTimeDown ();
 BendTimeUp ();
 }
 
 function BendTimeTrigger () {
 
     if (Input.GetKeyDown("t")) {
         count++;
     }
     
     if (count == 0) {
         BendTimeUpCompleted = false;
         bendTimeDown = false;
         bendTimeUp = false;
     }
     
     if (count == 1) {
         bendTimeDown = true;
         bendTimeUp = false;
         BendTimeUpCompleted = false;
     }
     if (count == 2) {
         bendTimeDown = false;
         bendTimeUp = true;
     }
     if (BendTimeUpCompleted == true) {
         count = 0;
     }
     
 }
 
 function BendTimeDown () {
     if (bendTimeUp == false) {
         if(bendTimeDown == true){
             if (Time.timeScale == 1.0) {
                 yield WaitForSeconds(.2);
                 Time.timeScale = 0.8;
                 Debug.Log (Time.timeScale);
             }
 
             if (Time.timeScale == 0.8) {
                 yield WaitForSeconds(.3);
                 Time.timeScale = 0.6;
                 Debug.Log (Time.timeScale);
             }
         
             if (Time.timeScale == 0.6) {
                 yield WaitForSeconds(.4);
                 Time.timeScale = 0.4;
                 Debug.Log (Time.timeScale);
             }
         
             if (Time.timeScale == 0.4) {
                 yield WaitForSeconds(.5);
                 Time.timeScale = 0.2;
                 Debug.Log (Time.timeScale);
             }
         }
     }
 }
 function BendTimeUp () {
 if (bendTimeDown == false) {
     if(bendTimeUp == true){
             if (Time.timeScale == 0.2) {
                 yield WaitForSeconds(.5);
                 Time.timeScale = 0.4;
                 Debug.Log (Time.timeScale);
             }
             
             if (Time.timeScale == 0.4) {
                 yield WaitForSeconds(.4);
                 Time.timeScale = 0.8;
                 Debug.Log (Time.timeScale);
             }
             
             if (Time.timeScale == 0.8) {
                 yield WaitForSeconds(.3);
                 Time.timeScale = 1;
                 BendTimeUpCompleted = true;
                 Debug.Log (Time.timeScale);
             }
         }    
     }
 }

Thanks Daniel