Scripting Curves, How To Maintain The Shape ?

Hello guys, I have a little problem. I am trying to learn how to script AnimationCurves, in order to change my Color Correction Curves Image Effect in runtime. I've figured out the most of it, but still I have a minor glitch to solve. First, here is the default value and the desired value of my red channel :

So I wrote this script:

 using UnityEngine;
 using System.Collections;
 using UnityStandardAssets.ImageEffects;
 
 public class IS_ActionImageEffects : MonoBehaviour {
 
     public Transform t_EffectsHolder;
     public float f_LerpSpeedRed;
     public float f_LerpSpeedRedBack;
     public bool b_WaitFirst;
     public float f_WaitFirst;
     public float f_WaitToLerpBack;
     private ColorCorrectionCurves _CorrectionCurves;
     private Vector2 v2_OriginalRedKey;
 
     void Awake()
     {
         _CorrectionCurves = t_EffectsHolder.GetComponent<ColorCorrectionCurves>();
     }
 
     void OnEnable()
     {
         
         StartCoroutine(LerpRedChannel());
 
         
     }
     
     IEnumerator LerpRedChannel()
     {
         if (b_WaitFirst)
             yield return new WaitForSeconds(f_WaitFirst);
 
         float i = 0.0f;
         float rate = 1.0f / f_LerpSpeedRed;
         float f_CurrentTime = _CorrectionCurves.redChannel.keys[1].time;
         float f_CurrentValue = _CorrectionCurves.redChannel.keys[1].value;
         v2_OriginalRedKey.x = f_CurrentTime;
         v2_OriginalRedKey.y = f_CurrentValue;
         float f_KeyTime;
         float f_KeyValue;
 
         while (i < 1.0f)
         {
             i += Time.deltaTime * rate;
             f_KeyTime = Mathf.Lerp(f_CurrentTime, 0.6f, i);
             f_KeyValue = Mathf.Lerp(f_CurrentValue, 0.3f, i);
             _CorrectionCurves.redChannel.MoveKey(1, new Keyframe(f_KeyTime, f_KeyValue));
             _CorrectionCurves.redChannel.SmoothTangents(1, 1);
             _CorrectionCurves.UpdateParameters();
             yield return null;
         }
 
         yield return new WaitForSeconds(f_WaitToLerpBack);
 
         i = 0.0f;
         float rate2 = 1.0f / f_LerpSpeedRedBack;
         float f_CurrentTime2 = _CorrectionCurves.redChannel.keys[1].time;
         float f_CurrentValue2 = _CorrectionCurves.redChannel.keys[1].value;
 
         while (i < 1.0f)
         {
             i += Time.deltaTime * rate2;
             f_KeyTime = Mathf.Lerp(f_CurrentTime2, v2_OriginalRedKey.x, i);
             f_KeyValue = Mathf.Lerp(f_CurrentValue2, v2_OriginalRedKey.y, i);
             _CorrectionCurves.redChannel.MoveKey(1, new Keyframe(f_KeyTime, f_KeyValue));
             _CorrectionCurves.redChannel.SmoothTangents(1, 1);
             _CorrectionCurves.UpdateParameters();
             yield return null;
         }
 
     }
 }

Which lerps 2 values in order to make the change smooth, waits, and lerps those values back. But the problem is, curves get, lets say, broken. I can't maintain the shape, here is the visual of the curve after the first while loop and after the second one :

It seems like something to do with my tries to maintain the things by using SmoothTangent, but I've tried:

 SmoothTangent(1,0);
 SmoothTangent(1,0.5f);
 SmoothTangent(1,1);

I've got slightly different results but none of them helped me solve the issue. So, what am I missing? Thanks in advance :)