Progress Bar and lerps

Hey My game has a Progress Bar and its fill rate depends on LERPS. Now the player has 5 choices to choose his pace of progress. I want everyone to get from point A to point B at the same time but their progress allowance will depend on the function Attaching script Thank you !!

using System.Collections; using System.Collections.Generic; using UnityEngine; using UnityEngine.UI; public class LerpsScript: MonoBehaviour {

 public Button Button;
 public Image progressBar;
 public Text txtAmount;
 public float minimum = 0.0F;
 public float maximum = 1.0F;

 public int switchFlag;
 public float workTime = 2.0f;
 bool doProgress = false;
 public float elapsedTime = 0f;

 public void OnClickButton()
 {
     elapsedTime = 0;//when the progress bar is 0%
     progressBar.fillAmount = 0;
     doProgress = true;// start 2 run 
     StartCoroutine(IEnum());
 }
 

 IEnumerator IEnum()
 {
     while (doProgress)
     {
         if (progressBar.fillAmount == 1.0f) // finish the progress bar 100 %
         {
             doProgress = false; //stop 2 run 
             progressBar.fillAmount = 0; // update 
         
         }
         else
         {
             if (switchFlag == 0)
             {

                 elapsedTime += Time.deltaTime/ workTime;
                 float curr = Mathf.Sin(elapsedTime * Mathf.PI * 0.5f);
                 progressBar.fillAmount += Mathf.Lerp(minimum, maximum, curr);
                
             }
             if (switchFlag == 1)
             {
                 elapsedTime += Time.deltaTime / workTime;
                 float curr = Mathf.Cos(elapsedTime * Mathf.PI * 0.5f); // curr=current
                 progressBar.fillAmount += Mathf.Lerp(minimum, maximum, curr);
             }
             if (switchFlag == 2)
             {
                elapsedTime += Time.deltaTime / workTime;
                float curr= elapsedTime * elapsedTime;
                progressBar.fillAmount += Mathf.Lerp(minimum, maximum, curr);
             }
             if (switchFlag == 3)
             {
                 elapsedTime += Time.deltaTime/ workTime;
                 float curr = elapsedTime * elapsedTime * (3f - 2f * elapsedTime);
                 progressBar.fillAmount += Mathf.Lerp(minimum, maximum, curr);
             }
             if(switchFlag==4)
             {
                 //elapsedTime += Time.deltaTime / workTime;
                 //float curr = elapsedTime * elapsedTime * elapsedTime * (elapsedTime * (6f * elapsedTime - 15f) + 10f);
                 //progressBar.fillAmount += Mathf.Lerp(progressBar.fillAmount, maximum, curr);
                 elapsedTime += Time.deltaTime/workTime;
                 float curr = elapsedTime;
                 progressBar.fillAmount = Mathf.Lerp(minimum, maximum, curr);
             }

         }
         yield return new WaitForSeconds(0.1f);
     }
 }

 public void OnValueChanged(Dropdown dropDown)
 {
     
     doProgress = false;
     progressBar.fillAmount = 0;

     StopCoroutine(IEnum());

     switch (dropDown.value)
     {

         case 0:
             Debug.Log("Yoho!");

             switchFlag = 0;
             break;
         case 1:
             Debug.Log("Wow!");
             switchFlag = 1;
             break;
         case 2:
             Debug.Log("Bla!");
             switchFlag = 2;
            
             break;
         case 3:
             Debug.Log("Whoo!");
             switchFlag = 3;
             break;
         case 4:
             Debug.Log("Good!");
             switchFlag = 4;
             break;
         default:
             Debug.Log("WTF!");
             break;
     }
 }

}