diff --git a/demo.html b/demo.html
index 9fdc571..bfda647 100644
--- a/demo.html
+++ b/demo.html
@@ -138,15 +138,16 @@ textarea {
       window.project1.Clear();
 
       var tasks = [
-        {"Order":1,"ID":1,"Name":"Task A","Description":"","Tag":null,"StartDate":"2024-08-11T23:00:00.000Z","FinishDate":"2024-08-14T23:00:00.000Z","StartDelay":0,"Duration":3,"PredecessorTaskID":null,"IsCollated":false,"CollatedTaskID":null,"CalcWorkHours":22.5,"ActuWorkHours":null,"Progress":0,"Resources":[],"Level":0,"PredecessorTaskNo":null},
-        {"Order":2,"ID":2,"Name":"Task B","Description":"","Tag":null,"StartDate":"2024-08-14T23:00:00.000Z","FinishDate":"2024-08-28T23:00:00.000Z","StartDelay":0,"Duration":14,"PredecessorTaskID":1,"IsCollated":false,"CollatedTaskID":null,"CalcWorkHours":105,"ActuWorkHours":null,"Progress":0,"Resources":[],"Level":0,"PredecessorTaskNo":1},
-        {"Order":3,"ID":5,"Name":"Task B1","Description":"","Tag":null,"StartDate":"2024-08-29T23:00:00.000Z","FinishDate":"2024-09-26T23:00:00.000Z","StartDelay":1,"Duration":28,"PredecessorTaskID":2,"IsCollated":true,"CollatedTaskID":null,"CalcWorkHours":210,"ActuWorkHours":null,"Progress":25,"Resources":[],"Level":0,"PredecessorTaskNo":2},
-        {"Order":4,"ID":6,"Name":"Task B11","Description":"","Tag":null,"StartDate":"2024-09-02T23:00:00.000Z","FinishDate":"2024-09-26T23:00:00.000Z","StartDelay":4,"Duration":24,"PredecessorTaskID":null,"IsCollated":false,"CollatedTaskID":5,"CalcWorkHours":180,"ActuWorkHours":null,"Progress":0,"Resources":[],"Level":1,"PredecessorTaskNo":null},
-        {"Order":5,"ID":7,"Name":"Task B12","Description":"","Tag":null,"StartDate":"2024-08-30T23:00:00.000Z","FinishDate":"2024-09-25T23:00:00.000Z","StartDelay":1,"Duration":26,"PredecessorTaskID":null,"IsCollated":false,"CollatedTaskID":5,"CalcWorkHours":0,"ActuWorkHours":null,"Progress":50,"Resources":[],"Level":1,"PredecessorTaskNo":null},
-        {"Order":6,"ID":8,"Name":"Task E","Description":"","Tag":null,"StartDate":"2024-08-11T23:00:00.000Z","FinishDate":"2024-08-26T23:00:00.000Z","StartDelay":0,"Duration":15,"PredecessorTaskID":null,"IsCollated":true,"CollatedTaskID":null,"CalcWorkHours":112.5,"ActuWorkHours":null,"Progress":0,"Resources":[],"Level":0,"PredecessorTaskNo":null},
-        {"Order":7,"ID":3,"Name":"Task C","Description":"","Tag":null,"StartDate":"2024-08-26T23:00:00.000Z","FinishDate":"2024-09-13T23:00:00.000Z","StartDelay":0,"Duration":18,"PredecessorTaskID":8,"IsCollated":false,"CollatedTaskID":null,"CalcWorkHours":135,"ActuWorkHours":null,"Progress":0,"Resources":[],"Level":0,"PredecessorTaskNo":6},
-        {"Order":8,"ID":4,"Name":"Task D","Description":"","Tag":null,"StartDate":"2024-09-14T23:00:00.000Z","FinishDate":"2024-09-24T23:00:00.000Z","StartDelay":1,"Duration":10,"PredecessorTaskID":3,"IsCollated":false,"CollatedTaskID":null,"CalcWorkHours":0,"ActuWorkHours":null,"Progress":0,"Resources":[],"Level":0,"PredecessorTaskNo":7},
-        {"Order":9,"ID":9,"Name":"Task E1","Description":"","Tag":null,"StartDate":"2024-08-14T23:00:00.000Z","FinishDate":"2024-08-26T23:00:00.000Z","StartDelay":3,"Duration":12,"PredecessorTaskID":null,"IsCollated":false,"CollatedTaskID":8,"CalcWorkHours":90,"ActuWorkHours":null,"Progress":0,"Resources":[],"Level":1,"PredecessorTaskNo":null}
+        {"ID":1,"Name":"Task A","Description":"","Tag":null,"StartDate":"2024-08-11T23:00:00.000Z","StartDelay":0,"Duration":3,"PredecessorTaskID":null,"IsCollated":false,"CollatedTaskID":null,"ActuWorkHours":null,"Progress":0,"Resources":[]},
+        {"ID":2,"Name":"Task B","Description":"","Tag":null,"StartDate":"2024-08-14T23:00:00.000Z","StartDelay":0,"Duration":14,"PredecessorTaskID":1,"IsCollated":false,"CollatedTaskID":null,"ActuWorkHours":null,"Progress":0,"Resources":[]},
+        {"ID":5,"Name":"Task B1","Description":"","Tag":null,"StartDate":"2024-08-29T23:00:00.000Z","StartDelay":1,"Duration":28,"PredecessorTaskID":2,"IsCollated":true,"CollatedTaskID":null,"ActuWorkHours":null,"Progress":25,"Resources":[]},
+        {"ID":6,"Name":"Task B11","Description":"","Tag":null,"StartDate":"2024-09-02T23:00:00.000Z","StartDelay":4,"Duration":24,"PredecessorTaskID":null,"IsCollated":false,"CollatedTaskID":5,"ActuWorkHours":null,"Progress":0,"Resources":[]},
+        {"ID":7,"Name":"Task B12","Description":"","Tag":null,"StartDate":"2024-08-30T23:00:00.000Z","StartDelay":1,"Duration":26,"PredecessorTaskID":null,"IsCollated":false,"CollatedTaskID":5,"ActuWorkHours":null,"Progress":50,"Resources":[]},
+        {"ID":8,"Name":"Task E","Description":"","Tag":null,"StartDate":"2024-08-11T23:00:00.000Z","StartDelay":0,"Duration":15,"PredecessorTaskID":null,"IsCollated":true,"CollatedTaskID":null,"ActuWorkHours":null,"Progress":0,"Resources":[]},
+        {"ID":3,"Name":"Task C","Description":"","Tag":null,"StartDate":"2024-08-26T23:00:00.000Z","StartDelay":0,"Duration":18,"PredecessorTaskID":8,"IsCollated":false,"CollatedTaskID":null,"ActuWorkHours":null,"Progress":0,"Resources":[]},
+        {"ID":4,"Name":"Task D","Description":"","Tag":null,"StartDate":"2024-09-14T23:00:00.000Z","StartDelay":1,"Duration":10,"PredecessorTaskID":3,"IsCollated":false,"CollatedTaskID":null,"ActuWorkHours":null,"Progress":0,"Resources":[]},
+        {"ID":9,"Name":"Task E1","Description":"","Tag":null,"StartDate":"2024-08-14T23:00:00.000Z","StartDelay":3,"Duration":12,"PredecessorTaskID":null,"IsCollated":false,"CollatedTaskID":8,"ActuWorkHours":null,"Progress":0,"Resources":[]},
+        {"ID":10,"Name":"Task C2","Description":"","Tag":null,"StartDate":"2024-08-26T23:00:00.000Z","StartDelay":0,"Duration":18,"PredecessorTaskID":8,"IsCollated":false,"CollatedTaskID":null,"ActuWorkHours":null,"Progress":0,"Resources":[]},
       ];
 
       tasks.forEach((e, i) => {
@@ -182,7 +183,7 @@ textarea {
       window.project1.Clear();
 
       var tasks = [
-      {"ID": 1, "Name": "task a","StartDelay": 0,"Duration": Math.randomN(0, 28),"PredecessorTaskID": null,"IsCollated": false,"CollatedTaskID": null},
+        {"ID": 1, "Name": "task a","StartDelay": 0,"Duration": Math.randomN(0, 28),"PredecessorTaskID": null,"IsCollated": false,"CollatedTaskID": null},
         {"ID": 2,"Name": "task b","StartDelay": Math.randomN(0, 5),"Duration": Math.randomN(0, 28),"PredecessorTaskID": 1,"IsCollated": false,"CollatedTaskID": null},
         {"ID": 5,"Name": "task b1","StartDelay": Math.randomN(0, 5),"Duration": Math.randomN(0, 28),"PredecessorTaskID": 2,"IsCollated": true,"CollatedTaskID": null},
         {"ID": 6,"Name": "task b11","StartDelay": Math.randomN(0, 5),"Duration": Math.randomN(0, 28),"PredecessorTaskID": null,"IsCollated": false,"CollatedTaskID": 5},
diff --git a/package.json b/package.json
index fb135cf..0e371c3 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "LiteRyzJS/Project",
-  "version": "0.2.0.256",
+  "version": "0.2.0.508",
   "devDependencies": {
     "css-loader": "^7.1.2",
     "sass": "^1.77.8",
diff --git a/src/project/gantt-chart.js b/src/project/gantt-chart.js
index 4413493..1dbe292 100644
--- a/src/project/gantt-chart.js
+++ b/src/project/gantt-chart.js
@@ -298,7 +298,7 @@ class GanttChart {
         style = a.Options.Row.CollatedTask;
       } else if (a.Tasks[i].CollatedTaskID != null) {
         style = a.Options.Row.ChildTask;
-      } else if (a.Tasks[i].PredecessorTaskNo == null) {
+      } else if (a.Tasks[i].PredecessorTaskID == null) {
         style = a.Options.Row.OrphanTask;
       }
 
@@ -320,7 +320,7 @@ class GanttChart {
         continue;
       }
 
-      if (a.Tasks[i].PredecessorTaskNo == null) {
+      if (a.Tasks[i].PredecessorTaskID == null) {
         continue;
       }
 
@@ -329,7 +329,7 @@ class GanttChart {
       const paddingX = (a.Options.Row.CollatedTask.Height + a.Options.BorderWidth);
       const offsetX = (rectangle.X + paddingX);
 
-      const predecessorTask = a.Tasks.first("Order", a.Tasks[i].PredecessorTaskNo);
+      const predecessorTask = a.Tasks.first("ID", a.Tasks[i].PredecessorTaskID);
       if (predecessorTask == null) {
         continue;
       }
diff --git a/src/project/project-node-model.js b/src/project/project-node-model.js
new file mode 100644
index 0000000..4d27008
--- /dev/null
+++ b/src/project/project-node-model.js
@@ -0,0 +1,24 @@
+import ProjectTaskModel from './project-task-model.js';
+
+import '../references/extensions.dist.js';
+
+
+class ProjectNodeModel extends ProjectTaskModel{
+  Order = null;
+  StartDate = null;
+  FinishDate = null;
+  CalcWorkHours = 0;
+  Level = 0;
+  Tasks = [];
+
+
+  constructor(options) {
+    super();
+
+    Object.assign(this, options);
+  }
+
+}
+
+
+export default ProjectNodeModel;
\ No newline at end of file
diff --git a/src/project/project-planner.js b/src/project/project-planner.js
index b75cfc3..0de5d43 100644
--- a/src/project/project-planner.js
+++ b/src/project/project-planner.js
@@ -8,7 +8,6 @@ class ProjectPlanner {
     const a = this;
 
     a.Container = el;
-
     a.Columns = [
       null,
       null,
@@ -20,6 +19,7 @@ class ProjectPlanner {
       "Resource Names",
       null
     ];
+    a.Tasks = [];
 
 		a.#initialiseComponents();
   }
@@ -52,6 +52,8 @@ class ProjectPlanner {
   Load(tasks) {
     const a = this;
 
+    a.Tasks = tasks;
+
     if (!a.Container.classList.contains("literyzjs-project")) {
       a.Container.classList.add("literyzjs-project");
     }
@@ -125,7 +127,7 @@ class ProjectPlanner {
     htmlContent += "<td>" + task.Duration + " day" + (parseInt(task.Duration) == 1 ? "" : "s") + "</td>";
     htmlContent += "<td class='c'>" + new Date(task.StartDate).toLocaleDateString() + "</td>";
     htmlContent += "<td class='c'>" + new Date(task.FinishDate).toLocaleDateString() + "</td>";
-    htmlContent += "<td class='c'>" + (task.PredecessorTaskNo ?? "") + "</td>";
+    htmlContent += "<td class='c'>" + a.#findTaskNo(task.PredecessorTaskID) + "</td>";
     htmlContent += "<td></td>";
     htmlContent += "<td></td>";
     htmlContent += "</tr>";
@@ -133,6 +135,18 @@ class ProjectPlanner {
     return htmlContent;
   }
 
+  #findTaskNo(id) {
+    const a = this;
+
+    if (id == null) {
+      return "";
+    }
+
+    const item = a.Tasks.first("ID", id);
+
+    return (item == null) ? "" : item.Order;
+  }
+
 }
 
 
diff --git a/src/project/project-task-model.js b/src/project/project-task-model.js
new file mode 100644
index 0000000..091722f
--- /dev/null
+++ b/src/project/project-task-model.js
@@ -0,0 +1,26 @@
+import '../references/extensions.dist.js';
+
+
+class ProjectTaskModel {
+  ID = null;
+  Name = "";
+  Description = "";
+  Tag = null;
+  StartDelay = 0;    // Days
+  Duration = 1;   // Days
+  PredecessorTaskID = null;
+  IsCollated = false;
+  CollatedTaskID = null;
+  ActuWorkHours = null;
+  Progress = 0;
+  Resources = [];
+
+
+  constructor(options) {
+    Object.assign(this, options);
+  }
+
+}
+
+
+export default ProjectTaskModel;
\ No newline at end of file
diff --git a/src/project/project.js b/src/project/project.js
index 682f6e0..600967f 100644
--- a/src/project/project.js
+++ b/src/project/project.js
@@ -1,3 +1,6 @@
+import ProjectTaskModel from './project-task-model.js';
+import ProjectNodeModel from './project-node-model.js';
+
 import '../references/extensions.dist.js';
 
 
@@ -6,33 +9,12 @@ class Project {
     const a = this;
     const _options = Object.assign(a.DefaultOptions, options);
 
-    a.Debug = false;
+    a.Debug = true;
     a.Project = _options;
     a.Tasks = [];
   }
 
 
-  get NewTask() {
-    return {
-      // Order: null,
-      ID: null,
-      Name: "",
-      Description: "",
-      Tag: null,
-      // StartDate: null,    // new Date(),
-      // FinishDate: null,   // new Date(),
-      StartDelay: 0,    // Days
-      Duration: 1,   // Days
-      PredecessorTaskID: null,
-      IsCollated: false,
-      CollatedTaskID: null,
-      // CalcWorkHours: 0,
-      ActuWorkHours: null,
-      Progress: 0,
-      Resources: []
-    };
-  }
-
   get StartDate() {
     const a = this;
 
@@ -72,35 +54,11 @@ class Project {
     };
   }
 
-  get #newTaskNode() {
-    return {
-      Order: null,
-      ID: null,
-      Name: "",
-      Description: "",
-      Tag: null,
-      StartDate: null,    // new Date(),
-      FinishDate: null,   // new Date(),
-      StartDelay: 0,    // Days
-      Duration: 1,   // Days
-      PredecessorTaskID: null,
-      IsCollated: false,
-      CollatedTaskID: null,
-      CalcWorkHours: 0,
-      ActuWorkHours: null,
-      Progress: 0,
-      Resources: [],
-      Level: 0,
-      PredecessorTaskNo: null,
-      Tasks: []
-    };
-  }
-
 
   AddTask(task) {
     const a = this;
-    const newTask = Object.assign(a.NewTask, task);
-    const newTaskNode = Object.assign(a.#newTaskNode, newTask);
+    const newTask = new ProjectTaskModel(task);
+    const newTaskNode = new ProjectNodeModel(newTask);
 
     if ((newTaskNode.PredecessorTaskID == null) && (newTaskNode.CollatedTaskID == null)) {
       a.Tasks.push(newTaskNode);
@@ -232,19 +190,18 @@ class Project {
     a.Sort();
 
     // Get flat references
-    let result = a.Tasks.flatten("Tasks");
+    let allTasks = a.Tasks.flatten("Tasks");
 
     // Reset calculated values
-    for (var i=0; i<result.length; i++) {
-      result[i].Order = (i + 1);
-      result[i].StartDate = null;
-      result[i].FinishDate = null;
-      result[i].CalcWorkHours = null;
+    for (var i=0; i<allTasks.length; i++) {
+      allTasks[i].Order = (i + 1);
+      allTasks[i].StartDate = null;
+      allTasks[i].FinishDate = null;
+      allTasks[i].CalcWorkHours = null;
     }
 
-    // Maximum 128 rounds
-    for (var x=0; x<128; x++) {
-      let pendingCount = result.copy().countMany(
+    for (var x=0; x<16; x++) {
+      let pendingCount = allTasks.countMany(
         { propName: "StartDate", value: null },
         { propName: "FinishDate", value: null }
       );
@@ -257,81 +214,11 @@ class Project {
 
       a.#log("Round " + (x + 1));
 
-      for (var i=0; i<result.length; i++) {
-        const nodeType = a.GetNodeType(result[i]);
-
-        switch (nodeType) {
-          case 1:     // task no-parent/root
-            result[i].StartDate = Date.addDays(a.Project.StartDate, result[i].StartDelay);
-            result[i].FinishDate = Date.addDays(result[i].StartDate, result[i].Duration);
-            break;
-          case 2:     // task no-parent/root, collated/group
-            result[i].StartDate = Date.addDays(a.Project.StartDate, result[i].StartDelay);
-            result[i].Progress = 0;
-
-            // update finish date, if possible
-            a.#recalculateCollatedTask(result, i);
-
-            break;
-          case 3:     // task with parent
-            const node3 = result.first("ID", result[i].PredecessorTaskID);
-            if (node3 != null) {
-              if (node3.FinishDate != null) {
-                result[i].StartDate = Date.addDays(node3.FinishDate, result[i].StartDelay);
-                result[i].FinishDate = Date.addDays(result[i].StartDate, result[i].Duration);
-              }
-            }
-
-            break;
-          case 4:     // task with parent, collated/group
-            const node4 = result.first("ID", result[i].PredecessorTaskID);
-            if (node4 != null) {
-              if (node4.FinishDate != null) {
-                result[i].StartDate = Date.addDays(node4.FinishDate, result[i].StartDelay);
-                result[i].Progress = 0;
-
-                // update finish date, if possible
-                a.#recalculateCollatedTask(result, i);
-              }
-            }
-
-            break;
-          case 5:     // sub-task
-            const node5 = result.first("ID", result[i].CollatedTaskID);
-            if (node5 != null) {
-              if (node5.StartDate != null) {
-                result[i].StartDate = Date.addDays(node5.StartDate, result[i].StartDelay);
-                result[i].FinishDate = Date.addDays(result[i].StartDate, result[i].Duration);
-                result[i].Level = (node5.Level + 1);
-              }
-            }
-
-            break;
-          case 6:     // sub-task, collated/group
-            const node6 = result.first("ID", result[i].CollatedTaskID);
-            if (node6 != null) {
-              if (node6.StartDate != null) {
-                result[i].StartDate = Date.addDays(node6.StartDate, result[i].StartDelay);
-                result[i].Progress = 0;
-                result[i].Level = (node6.Level + 1);
-
-                // update finish date, if possible
-                a.#recalculateCollatedTask(result, i);
-              }
-            }
-
-            break;
-          default:    // orphan
-            break;
-        }
-      }
+      a.#recalculateTask(allTasks, a.Tasks);
     }
 
     // Calculate work-hours
-    a.#recalculateWorkHours(result);
-
-    // Calculate predecessor
-    a.#recalculatePredecessorTaskNo(result);
+    a.#recalculateWorkHours(allTasks);
 
     return isSuccess;
   }
@@ -378,51 +265,75 @@ class Project {
     }
   }
 
-  #recalculatePredecessorTaskNo(array) {
+  #recalculateTask(allTasks, tasks) {
     const a = this;
 
-    for (var i=0; i<array.length; i++) {
-      if (array[i].PredecessorTaskID == null) {
-        continue;
+    for (let i=0; i<tasks.length; i++) {
+      const task = tasks[i];
+
+      a.#log(task.Name);
+
+      if (task.PredecessorTaskID != null) {
+        const parentTask = allTasks.first("ID", task.PredecessorTaskID);
+        if (parentTask != null) {
+          if (parentTask.FinishDate != null) {
+            task.StartDate = Date.addDays(parentTask.FinishDate, task.StartDelay);
+
+            a.#log("> Set StartDate from Predecessor");
+          }
+        }
+      } else if (task.CollatedTaskID != null) {
+          const groupTask = allTasks.first("ID", task.CollatedTaskID);
+          if (groupTask != null) {
+            if (groupTask.StartDate != null) {
+              task.StartDate = Date.addDays(groupTask.StartDate, task.StartDelay);
+
+              a.#log("> Set StartDate from Group");
+            }
+          }
+      } else {
+        task.StartDate = Date.addDays(a.Project.StartDate, task.StartDelay);
+
+        a.#log("> Set StartDate from Project");
       }
 
-      const predecessor = a.FindTask(array[i].PredecessorTaskID);
-      if (predecessor == null) {
-        continue;
+      // if (task.IsCollated) {
+      if (task.Tasks.length > 0) {
+        a.#recalculateTask(allTasks, task.Tasks);
+
+        a.#log("> Calc inner");
+      }
+      // }
+
+      if (task.StartDate != null) {
+        if (task.IsCollated) {
+
+          const childTasks = task.Tasks.select("CollatedTaskID", task.ID);
+          if (childTasks.length <= 0) {
+            task.FinishDate = task.StartDate;
+            task.Duration = 0;
+
+            a.#log("> Set FinishDate from Group (0)");
+          } else {
+
+            if (!childTasks.any("FinishDate", null)) {
+              task.FinishDate = childTasks.orderByDesc("FinishDate")[0].FinishDate;
+              task.Duration = Date.diffDays(task.StartDate, task.FinishDate);
+
+              a.#log("> Set FinishDate from Group");
+            }
+          }
+
+        } else {
+          task.FinishDate = Date.addDays(task.StartDate, task.Duration);
+
+          a.#log("> Set FinishDate");
+        }
       }
 
-      array[i].PredecessorTaskNo = predecessor.Order;
     }
   }
 
-  #recalculateCollatedTask(array, index) {
-    let node2 = array.select("CollatedTaskID", array[index].ID);
-    if (node2.length <= 0) {
-      // No children
-      array[index].Duration = 0;
-
-      return new Date(array[index].StartDate);
-    }
-
-    // Not ready, calculation pending
-    if (node2.any("FinishDate", null)) {
-      array[index].Duration = 0;
-
-      return null;
-    }
-
-    let node2FinishDate = new Date(array[index].StartDate);
-    node2.forEach(e => {
-      if (e.FinishDate > node2FinishDate) {
-        node2FinishDate = e.FinishDate;
-      }
-    });
-
-    array[index].Progress = Math.average(node2.toList("Progress"));
-    array[index].FinishDate = new Date(node2FinishDate);
-    array[index].Duration = Date.diffDays(array[index].StartDate, array[index].FinishDate);
-  }
-
   #sortNode(node) {
     const a = this;