Custom Inspector Array Elements not saving

So, I'm trying to create a Custom Inspector for an array of custom classes, and I would like to have the ability to change the class of the array element based on a dropdown list. In my case, I have an array of the base class (Command), and I would like to be able to change the element to either a TestCommand instance or a TestLongCommand instance (both of which inherit from Command). The problem now is that when I change the elements, THE VALUE IS NEVER SAVED. Even after I set them to dirty, and set them serializable. So even if I create a list which has a 3 TestCommands and 2 TestLongCommands, they all become 5 Commands when I reload the scene/press play. Could somebody please help me out? I've been searchin for like 4 hours and haven't been able to find the solution to my problem...

CommandList.cs

 [System.Serializable]
 public class Command {
 
     public virtual string commandName{
         get { return this.GetType().Name;}
     }
     ...
 }
 
 [System.Serializable]
 public class CommandList : MonoBehaviour {
     public List<Command> commands;
     public int currCommandIndex = 0;
         ...
 }

CommandListEditor.cs

 [CustomEditor(typeof(CommandList))]
 public class CommandListEditor : Editor {
 
     CommandList script;
 
     void OnEnable()
     {
         script = (CommandList)target;
     }
 
     public override void OnInspectorGUI()
     {
         serializedObject.Update();
         EditorGUILayout.PrefixLabel("Commands");
         SerializedProperty commandsProp = serializedObject.FindProperty("commands");
 
         List<string> allTypeStrings = new List<string>();
         System.Type[] allTypes = Methods.GetSubclasses<Command>();
         foreach(System.Type type in allTypes)
         {
             allTypeStrings.Add(type.Name);
         }
 
         int i = 0;
         foreach(SerializedProperty childProp in commandsProp)
         {
             EditorGUILayout.LabelField("[" + i.ToString() + "]");
             //Debug.Log(currValue);
 
             int currIndex = -1;
             if (script.commands[i] != null)
             {
                 for (int j = 0; j < allTypeStrings.Count; ++j)
                 {
                     if (allTypeStrings[j] == script.commands[i].commandName)
                         currIndex = j;
                 }
                 EditorGUILayout.LabelField(script.commands[i].commandName);
             }
 
             int newIndex = EditorGUILayout.Popup(currIndex, allTypeStrings.ToArray());
             if (newIndex != currIndex)
             {
                 Debug.Log("Changed from " + ((script.commands[i] != null)?script.commands[i].commandName:"NULL") + " to " + allTypeStrings[newIndex] + " in " + serializedObject.targetObject.name);
 System.Activator.CreateInstance(allTypes[newIndex]) as Command);
 
                 script.commands[i] = System.Activator.CreateInstance(allTypes[newIndex]) as Command;
 
             }
 
             childProp.serializedObject.ApplyModifiedProperties();
             commandsProp.serializedObject.ApplyModifiedProperties();
 
             ++i;
         }
 
         if (GUI.changed)
         {
             EditorUtility.SetDirty(script);
             EditorUtility.SetDirty(script.gameObject);
             Undo.RecordObject(script, "Changed command");
             EditorSceneManager.MarkSceneDirty(script.gameObject.scene);
 
             Debug.Log("CHANGED!");
         }
 
         serializedObject.ApplyModifiedProperties();
     }
 
 }