Why isn't the DetailPrototype being added through a script waving?

I have created an EditorWindow script to create a terrain object in my scene. The script uses a block of information that I am storing in another game object. The game object with the information script on it gives inputs for DetailPrototypes that I want to add to the terrain. This all works fine, except that any prototypes I add to this terrain in this way do not sway when being used with the "Grass" render mode. However, if I then manually create a prototype in the normal inspector interface, then the prototype does indeed wave.

Is there something I am not "turning on" in the DetailPrototype object when I adding it in the script?

Here is the function where the terrain is created (look for the "Initialize Details" portion):

     void CreateTerrain()
     {
         if (GOInitializer == null) return;
         if (GOInitializer.GetComponent<TerrainConstructorSettings>() == null) return;
         if (Settings == null) InitializeSettings();
 
 
         // Get rid of old version of the Terrain  --------------------------------------------
         WorldName = Settings.WorldName;
         string TerrainName = WorldName + "_Tile_" + Position.X.ToString() + "_" + Position.Z.ToString();
         if (GameObject.Find(TerrainName) != null)
         {
             GameObject oldgo = GameObject.Find(TerrainName);
             DestroyImmediate(oldgo);
         }
 
         // Initialize the Terrain Data  ------------------------------------------------------
 
         TDATA = new TerrainData();
         TDATA.heightmapResolution = Settings.HeightmapResolution;
         TDATA.alphamapResolution = Settings.AlphamapResolution;
         TDATA.SetDetailResolution(Settings.AlphamapResolution, 8);
         AssetDatabase.CreateAsset(TDATA, "Assets/Resources/" + WorldName + "/TerrainData/" + TerrainName + ".asset");
 
         TDATA.SetHeights(0, 0, GenerateHeightmap());
 
         // Initialize the textures ------------------------------------------------------------
         
         SplatPrototype[] sprot = new SplatPrototype[Settings.terrain_textures.Length];
 
         for (int i = 0; i < Settings.terrain_textures.Length; i++)
         {
             TextInfo TI = Settings.terrain_textures[i];
             sprot[i] = new SplatPrototype();
             sprot[i].texture = TI.tex0;
             sprot[i].normalMap = TI.texn;
             sprot[i].tileSize = new Vector2(TI.scale, TI.scale);
         }
         TDATA.splatPrototypes = sprot;
 
         // Initialize the details  ------------------------------------------------------------
         DetailPrototype[] DPROTS = new DetailPrototype[Settings.terrain_Details.Length];
         for(int i = 0; i < DPROTS.Length; i++)
         {
             DPROTS[i] = new DetailPrototype();
             DPROTS[i].renderMode = Settings.terrain_Details[i].mode;
             if (DPROTS[i].renderMode == DetailRenderMode.GrassBillboard)
             {
                 DPROTS[i].prototypeTexture = Settings.terrain_Details[i].grass_tex;
             }
             else
             {
                 DPROTS[i].prototype = Settings.terrain_Details[i].prefab;
             }
             if (DPROTS[i].prototype != null) DPROTS[i].usePrototypeMesh = true;
             DPROTS[i].bendFactor = 1f;// Settings.terrain_Details[i].bendFactor;
             DPROTS[i].dryColor = Settings.terrain_Details[i].dry_color;
             DPROTS[i].healthyColor = Settings.terrain_Details[i].healthy_color;
             if (Settings.terrain_Details[i].minWidth != 0) DPROTS[i].minWidth = Settings.terrain_Details[i].minWidth;
             if (Settings.terrain_Details[i].maxWidth != 0) DPROTS[i].maxWidth = Settings.terrain_Details[i].maxWidth;
             if (Settings.terrain_Details[i].minHeight != 0) DPROTS[i].minHeight = Settings.terrain_Details[i].minHeight;
             if (Settings.terrain_Details[i].maxHeight != 0) DPROTS[i].maxHeight = Settings.terrain_Details[i].maxHeight;
 
         }
         TDATA.wavingGrassAmount = 0.5f;
         TDATA.wavingGrassSpeed = 0.5f;
         TDATA.wavingGrassStrength = 0.5f;
 
         TDATA.detailPrototypes = DPROTS;
         TDATA.RefreshPrototypes();
 
         // Add TreePrototypes  ------------------------------------------------------------
 
         TreePrototype treeproto = new TreePrototype();
         treeproto.prefab = Settings.Tree1;
 
         TDATA.treePrototypes = new TreePrototype[]
         {
                 treeproto,
         };
 
         // Create the terrain object and set Terrain Parameters  ---------------------------------------------------------
 
         TDATA.size = new Vector3(Settings.Length, Settings.Height, Settings.Length);
         var newTerrainGameObject = Terrain.CreateTerrainGameObject(TDATA);
         newTerrainGameObject.transform.position = new Vector3(Position.X * Settings.Length, 0, Position.Z * Settings.Length);
         newTerrainGameObject.name = TerrainName;
 
         T = newTerrainGameObject.GetComponent<Terrain>();
 
         T.terrainData.RefreshPrototypes();
         T.basemapDistance = 1000f;
         T.treeDistance = 1000f;
         T.heightmapPixelError = Settings.PixelError;
         T.reflectionProbeUsage = UnityEngine.Rendering.ReflectionProbeUsage.Off;
         T.detailObjectDistance = 200f;
 
         CompleteTerrainShader cTS = newTerrainGameObject.AddComponent(typeof(CompleteTerrainShader)) as CompleteTerrainShader;
         cTS.AutoBakeNormalMap = false;
         cTS.AutoBakeColorMap = false;
         cTS.Profile = Settings.cTS_Profile;
 
         T.Flush();
 
         // Save the game object as a prefab to the resource folder
         PrefabUtility.CreatePrefab("Assets/Resources/" + WorldName + "/" + TerrainName + ".prefab",newTerrainGameObject);
     }