Player Health Glitch?

I have built a player health system with a health bar, and everything seems to be working fine, the only problem is that the system will not work with a 4 health maximum. Here is the script:

public class PlayerHealth : MonoBehaviour {

 public GameObject blood;
 public float Health;
 public float MaxHealth;
 public Image HealthBarFill;

 void Update () {
     HealthBarFill.fillAmount = Health / MaxHealth;
     if(Health <= 0)
     {
         Destroy(gameObject);
     }
     if(Health > MaxHealth)
     {
         Health = MaxHealth;
     }
 
 }
 
 void OnCollisionEnter (Collision col) {
     if(col.gameObject.tag == "EnemyBullet")
     {
         Instantiate(blood, this.transform.position + this.transform.forward/2, this.transform.rotation);
         Health -= 1;
     }
 }

}

Now, if I set the player health/max health in the inspector to 5 or higher, it works just fine. Five hits to die and the bar reflects 5 health. If I do 8, it also works fine. If I put it on 4 or lower, I only get two hits. The bar works fine. It reflects the two hits, but if I set it to 4, it's just two health. 3 is just two hits to die. 2 works fine, only two health. At first, I thought it was just registering multiple hits on the collision, but that does not appear to be the case. It counts the health 100% accurately on anything above four, but 4 is the actual amount I wanted to use, and now I just want to know what is wrong. Any ideas?