Auto grass placement not working properly

Hello, I have this script which I found online that allows me to automatically add grass to specific textures on my terrain it works nicely except if I make the detailCountPerDetailPixel to bigger than 1 (I need to make it bigger to make my grass a little more dense) it only creates stripes of grass at certain points of the terrain which obviously isn't the correct behavior so if someone wants to try to take a look at this or redirect me to better and newer solution I'd me thankful.

using UnityEngine; using UnityEditor;

public class GrassCreator : EditorWindow {

 public Terrain terrain;
 public int detailIndexToMassPlace;
 public int[] splatTextureIndicesToAffect = new int[] { 0, };
 public int detailCountPerDetailPixel = 1;
 
 [MenuItem("Tools/Mass Grass Placement")]
 
 static void Init()
 {
     GrassCreator window = (GrassCreator)GetWindow(typeof(GrassCreator));
     window.Show();
     window.titleContent = new GUIContent("Grass Creator");
     window.Focus();
     window.ShowUtility();
     if (Selection.activeGameObject && Selection.activeGameObject.GetComponent<Terrain>())
     {
         window.terrain = Selection.activeGameObject.GetComponent<Terrain>();
     }
 }
 
 void OnGUI()
 {
     GUILayout.Label("Grass Creator", EditorStyles.boldLabel);
     GUILayout.Label("Settings for Grass", EditorStyles.centeredGreyMiniLabel);
 
     ScriptableObject ter = this;
     SerializedObject terrainso = new SerializedObject(ter);
     SerializedProperty property = terrainso.FindProperty("terrain");
     EditorGUILayout.PropertyField(property, new GUIContent("Terrain Object:", "Place your terrain object in here."), true);
     terrainso.ApplyModifiedProperties();
 
     if (terrain != null)
     {
         detailCountPerDetailPixel = EditorGUILayout.IntSlider(new GUIContent("Detail Counter Per Detail Pixel:", "The detail count per detail pixel"), detailCountPerDetailPixel, 1, 16);
         detailIndexToMassPlace = EditorGUILayout.IntSlider(new GUIContent("Detail Index to Place:", "Select the grass index to mass place"), detailIndexToMassPlace, 0, terrain.terrainData.detailPrototypes.Length - 1);
 
         ScriptableObject target = this;
         SerializedObject so = new SerializedObject(target);
         SerializedProperty stringsProperty = so.FindProperty("splatTextureIndicesToAffect");
         EditorGUILayout.PropertyField(stringsProperty, new GUIContent("Splat Textures to place on:", "Indicate the splatmap index to place on."), true);
         so.ApplyModifiedProperties();
 
         if (GUILayout.Button(new GUIContent("Mass Place Grass", "Work the magic :D")))
         {
             CreateGrass();
         }
     }
 }
 
 void CreateGrass()
 {
 
     if (!terrain)
     {
         Debug.LogError("You have not selected a terrain object");
         return;
     }
 
     if (detailIndexToMassPlace >= terrain.terrainData.detailPrototypes.Length)
     {
         Debug.LogError("You have chosen a detail index which is higher than the number of detail prototypes in your detail libary. Indices starts at 0");
         return;
     }
 
     if (splatTextureIndicesToAffect.Length > terrain.terrainData.splatPrototypes.Length)
     {
         Debug.LogError("You have selected more splat textures to paint on, than there are in your libary.");
         return;
     }
 
     for (int i = 0; i < splatTextureIndicesToAffect.Length; i++)
     {
         if (splatTextureIndicesToAffect[i] >= terrain.terrainData.splatPrototypes.Length)
         {
             Debug.LogError("You have chosen a splat texture index which is higher than the number of splat prototypes in your splat libary. Indices starts at 0");
             return;
         }
     }
 
     if (detailCountPerDetailPixel > 16)
     {
         Debug.LogError("You have selected a non supported amount of details per detail pixel. Range is 0 to 16");
         return;
     }
 
     int alphamapWidth = terrain.terrainData.alphamapWidth;
     int alphamapHeight = terrain.terrainData.alphamapHeight;
     int detailWidth = terrain.terrainData.detailResolution;
     int detailHeight = detailWidth;
     float resolutionDiffFactor = (float)alphamapWidth / detailWidth;
     float[,,] splatmap = terrain.terrainData.GetAlphamaps(0, 0, alphamapWidth, alphamapHeight);
     int[,] newDetailLayer = new int[detailWidth, detailHeight];
 
     for (int i = 0; i < splatTextureIndicesToAffect.Length; i++)
     {
 
         for (int j = 0; j < detailWidth; j++)
         {
 
             for (int k = 0; k < detailHeight; k++)
             {
                 float alphaValue = splatmap[(int)(resolutionDiffFactor * j), (int)(resolutionDiffFactor * k), splatTextureIndicesToAffect[i]];
                 newDetailLayer[j, k] = (int)Mathf.Round(alphaValue * ((float)detailCountPerDetailPixel)) + newDetailLayer[j, k];
             }
 
         }
 
     }
     terrain.terrainData.SetDetailLayer(0, 0, detailIndexToMassPlace, newDetailLayer);
 }

}

little more info, the bigger the detailCountPerDetailPixel gets the smaller the stripes become here are few examples on how the stripes look like.