Power up not working - c++11

Question

So I currently have a working 'Speed' power up that multiplies the speed of the player by 2. I'm trying to make a power up now that increases the score you get for picking up the GameObject 'Gem' by 2. it should increase to 20 points per gem from 10.
Currently, the power up is spawning randomly around the map within 10-20 seconds, so as intended, but the score you get for collecting the power up has not gone up to 20.
PlayerMovement Code:
public float speed = 10f;
private Rigidbody2D rb2d;
public GameObject Player;
public GameObject speedPowerUp;
public static int livess = 100;
public Vector2 movement;
public GameObject MultiPowerUp;
public static int addScore = 10;
void Start ()
{
rb2d = GetComponent<Rigidbody2D> ();
}
void FixedUpdate ()
{
float moveHorizontal = Input.GetAxis ("Horizontal"); //Gets keys that unity refers to being able to move horizontal (Set by default)
float moveVertical = Input.GetAxis ("Vertical"); //Gets keys that unity refers to being able to move vertical (Set by default) Use forces to act with RigidBody2D
Vector2 movement = new Vector2 (moveHorizontal, moveVertical);
rb2d.AddForce (movement * speed);
if(moveHorizontal < 0)
GetComponent<SpriteRenderer>().flipX = true;
else if(moveHorizontal > 0)
GetComponent<SpriteRenderer>().flipX = false;
}
void OnTriggerEnter2D(Collider2D other)
{
if (other.gameObject.CompareTag ("shuriken"))
{
if (livess <= 1)
{
Destroy (Player);
livess = livess - 1;
Debug.LogError (livess);
}
else
{
livess = livess - 1;
Debug.LogError (livess);
return;
}
}
if (other.gameObject.CompareTag ("speedPowerUp"))
{
StartCoroutine (WaitTimeSpeed ());
other.gameObject.SetActive (false);
}
if (other.gameObject.CompareTag ("MultiPowerUp"))
{
StartCoroutine (WaitTimeMulti ());
other.gameObject.SetActive (false);
}
}
IEnumerator WaitTimeSpeed ()
{
Debug.LogError (speed);
speed = speed * 2;
Debug.LogError (speed);
yield return new WaitForSeconds (5);
speed = speed / 2;
Debug.LogError (speed);
yield return new WaitForSeconds (Random.Range (10, 20));
SpawnSpeed ();
}
void SpawnSpeed()
{
Vector3 RandomSpawn = new Vector3 (Random.Range (-8.87F, 8.87F), Random.Range (-3.87F, 3.97F),1F);
Instantiate (speedPowerUp, RandomSpawn, Quaternion.identity);
}
IEnumerator WaitTimeMulti()
{
Debug.LogError (addScore);
addScore = 20;
Debug.LogError (addScore);
yield return new WaitForSeconds (5);
addScore = 10;
yield return new WaitForSeconds (Random.Range (10, 20));
SpawnMulti ();
}
void SpawnMulti ()
{
Vector3 RandomSpawn = new Vector3 (Random.Range (-8.87F, 8.87F), Random.Range (-3.87F, 3.97F),1F);
Instantiate (MultiPowerUp, RandomSpawn, Quaternion.identity);
}
}
Gem Code:
public GameObject Gem;
public static int count;
public Text countText;
public int addScores = PlayerMovement.addScore;
void Start()
{
SetCountText ();
}
void SpawnGem()
{
Vector3 RandomSpawn = new Vector3 (Random.Range (-8.87F, 8.87F), Random.Range (-3.87F, 3.97F),1F);
Instantiate (Gem, RandomSpawn, Quaternion.identity);
}
void OnTriggerEnter2D(Collider2D other)
{
if (other.gameObject.CompareTag ("Player"))
{
SpawnGem ();
count = count + addScores;
SetCountText ();
PlayerPrefs.SetInt("Player Score", count);
Destroy (Gem);
}
}
void SetCountText()
{
countText.text = "Count: " + count.ToString ();
}
}