Increase scroll speed based on Score of my challenges

Hello! I want to create a 2D Jump'n Run platformer which has an endless mode. It has challenges (obstacles) which are spawning out of the camera view. Now I want to increase the scrolling speed of the challenges based on the score the player has reached to make the game more difficult. I already have created a possibility of it, but I think there's a better way to do that. If someone has an idea, please let me know it, thanks.

public class ChallengeController : MonoBehaviour {

 public float scrollSpeed = 5.0f;
 public GameObject[] challenges;
 public float frequency = 0.5f;
 float counter = 0.0f;
 public Transform challengesSpawnPoint;
 bool isGameOver = false;



 public float scrollSpeedMultiplier = 1.2f;     
 public GameController gameController;
 public ScoreManager myScoreManager;



 // Use this for initialization
 void Start () 
 {
     gameController = GameObject.Find ("GameController").GetComponent<GameController> ();
     myScoreManager = GameObject.Find ("ScoreManager").GetComponent<ScoreManager> ();
     GenerateRandomChallenge ();

 }
 
 // Update is called once per frame
 void Update () 
 {
     if (isGameOver) return;


     //Generate Objects
     if (counter <= 0.0f) {
         GenerateRandomChallenge ();
     } 
     else 
     {
         counter -= Time.deltaTime * frequency;
     }


     //scrolling
     GameObject currentChild;
     for (int i = 0; i < transform.childCount; i++) 
     {
         currentChild = transform.GetChild (i).gameObject;
         ScrollChallenge (currentChild);
         if (currentChild.transform.position.x <= -15.0f) 
         {
             Destroy (currentChild);
         }
     }

//This is my idea of increasing the scroll speed based on the score

     if(myScoreManager.scoreCount >= 50)
         scrollSpeed = 6;
     if(myScoreManager.scoreCount >= 100)
         scrollSpeed = 7;
     if(myScoreManager.scoreCount >= 150)
         scrollSpeed = 8;
     if(myScoreManager.scoreCount >= 200)
         scrollSpeed = 9;

//End

 }


 void ScrollChallenge (GameObject currentChallenge)
 {
     currentChallenge.transform.position -= Vector3.right * (scrollSpeed * Time.deltaTime);
 }


 void GenerateRandomChallenge()
 {
     GameObject newChallenge = Instantiate (challenges [Random.Range (0, challenges.Length)], challengesSpawnPoint.position, Quaternion.identity) as GameObject;
     newChallenge.transform.parent = transform;
     counter = 1.0f;
 }

 public void GameOver()
 {
     isGameOver = true;
     transform.GetComponent<GameController> ().GameOver ();

 }

}