Wrong use of Open/Closed principle

boss.cs

public enum BossType
{
  Good,
  Bad
}

public class Boss
{
  public string Name { get; set; }
  public double Money { get; set; }
  public BossType Type { get; set; }
}

service.cs

public class Service
{
  public List<Boss> Bosses { get; set; }
  public void addMoney()
  {
    foreach (var boss in Bosses)
    {
       double newMoney = 0;
       switch (boss.Type)
       {
         case BossType.Good:
           newMoney = boss.Money + 100;
           break;
         case BossType.Bad:
           newMoney = boss.Money - 100;
           break;
       }
       boss.Money = newMoney;
    }
  }
}