diff --git a/ClosedXML/Excel/PivotTables/IXLPivotFields.cs b/ClosedXML/Excel/PivotTables/IXLPivotFields.cs
index 08c5312..df5a497 100644
--- a/ClosedXML/Excel/PivotTables/IXLPivotFields.cs
+++ b/ClosedXML/Excel/PivotTables/IXLPivotFields.cs
@@ -1,17 +1,22 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
-using System.Text;
 
 namespace ClosedXML.Excel
 {
-    public interface IXLPivotFields: IEnumerable<IXLPivotField>
+    public interface IXLPivotFields : IEnumerable<IXLPivotField>
     {
         IXLPivotField Add(String sourceName);
-        IXLPivotField Add(String sourceName, String customName);
-        void Clear();
-        void Remove(String sourceName);
 
-        int IndexOf(IXLPivotField pf);
+        IXLPivotField Add(String sourceName, String customName);
+
+        void Clear();
+
+        Boolean Contains(String sourceName);
+
+        IXLPivotField Get(String sourceName);
+
+        Int32 IndexOf(IXLPivotField pf);
+
+        void Remove(String sourceName);
     }
 }
diff --git a/ClosedXML/Excel/PivotTables/XLPivotFields.cs b/ClosedXML/Excel/PivotTables/XLPivotFields.cs
index c1a52f2..19accb7 100644
--- a/ClosedXML/Excel/PivotTables/XLPivotFields.cs
+++ b/ClosedXML/Excel/PivotTables/XLPivotFields.cs
@@ -1,13 +1,40 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Text;
 
 namespace ClosedXML.Excel
 {
-    public class XLPivotFields: IXLPivotFields
+    public class XLPivotFields : IXLPivotFields
     {
         private readonly Dictionary<String, IXLPivotField> _pivotFields = new Dictionary<string, IXLPivotField>();
+
+        public IXLPivotField Add(String sourceName)
+        {
+            return Add(sourceName, sourceName);
+        }
+
+        public IXLPivotField Add(String sourceName, String customName)
+        {
+            var pivotField = new XLPivotField(sourceName) { CustomName = customName };
+            _pivotFields.Add(sourceName, pivotField);
+            return pivotField;
+        }
+
+        public void Clear()
+        {
+            _pivotFields.Clear();
+        }
+
+        public Boolean Contains(String sourceName)
+        {
+            return _pivotFields.ContainsKey(sourceName);
+        }
+
+        public IXLPivotField Get(string sourceName)
+        {
+            return _pivotFields[sourceName];
+        }
+
         public IEnumerator<IXLPivotField> GetEnumerator()
         {
             return _pivotFields.Values.GetEnumerator();
@@ -18,32 +45,17 @@
             return GetEnumerator();
         }
 
-        public IXLPivotField Add(String sourceName)
+        public Int32 IndexOf(IXLPivotField pf)
         {
-            return Add(sourceName, sourceName);
-        }
-        public IXLPivotField Add(String sourceName, String customName)
-        {
-            var pivotField = new XLPivotField(sourceName) {CustomName = customName};
-            _pivotFields.Add(sourceName, pivotField);
-            return pivotField;
-        }
-
-        public void Clear()
-        {
-            _pivotFields.Clear();
-        }
-        public void Remove(String sourceName)
-        {
-            _pivotFields.Remove(sourceName);
-        }
-
-        public int IndexOf(IXLPivotField pf)
-        {
-            var selectedItem = _pivotFields.Select((item, index) => new {Item = item, Position = index}).FirstOrDefault(i => i.Item.Key == pf.SourceName);
+            var selectedItem = _pivotFields.Select((item, index) => new { Item = item, Position = index }).FirstOrDefault(i => i.Item.Key == pf.SourceName);
             if (selectedItem == null)
                 throw new IndexOutOfRangeException("Invalid field name.");
             return selectedItem.Position;
         }
+
+        public void Remove(String sourceName)
+        {
+            _pivotFields.Remove(sourceName);
+        }
     }
 }
diff --git a/ClosedXML/Excel/XLWorkbook_Save.cs b/ClosedXML/Excel/XLWorkbook_Save.cs
index 57edc21..91f8e8c 100644
--- a/ClosedXML/Excel/XLWorkbook_Save.cs
+++ b/ClosedXML/Excel/XLWorkbook_Save.cs
@@ -146,7 +146,6 @@
             if (worksheet == null)
                 return;
 
-
             string sheetName = worksheet.Name;
             // Get the pivot Table Parts
             IEnumerable<PivotTableCacheDefinitionPart> pvtTableCacheParts = wbPart.PivotTableCacheDefinitionParts;
@@ -204,11 +203,9 @@
                 foreach (CalculationCell Item in calChainEntries)
                     calcsToDelete.Add(Item);
 
-
                 foreach (CalculationCell Item in calcsToDelete)
                     Item.Remove();
 
-
                 if (!calChainPart.CalculationChain.Any())
                     wbPart.DeletePart(calChainPart);
             }
@@ -1964,7 +1961,11 @@
             {
                 var columnNumber = c.ColumnNumber();
                 var columnName = c.FirstCell().Value.ToString();
-                var xlpf = pt.Fields.Add(columnName);
+                IXLPivotField xlpf;
+                if (pt.Fields.Contains(columnName))
+                    xlpf = pt.Fields.Get(columnName);
+                else
+                    xlpf = pt.Fields.Add(columnName);
 
                 var field =
                     pt.RowLabels.Union(pt.ColumnLabels).Union(pt.ReportFilters).FirstOrDefault(f => f.SourceName == columnName);
@@ -2150,10 +2151,12 @@
                     case XLPivotSubtotals.DoNotShow:
                         pf.DefaultSubtotal = false;
                         break;
+
                     case XLPivotSubtotals.AtBottom:
                         pf.DefaultSubtotal = true;
                         pf.SubtotalTop = false;
                         break;
+
                     case XLPivotSubtotals.AtTop:
                         pf.DefaultSubtotal = true;
                         pf.SubtotalTop = true;