diff --git a/VectoCore/VectoCore/Models/Simulation/Impl/SimulatorFactory.cs b/VectoCore/VectoCore/Models/Simulation/Impl/SimulatorFactory.cs
index 4d407871a953d06371c48f4ee1b8342130cf1628..256997d9838ec193531585c00293597683a52e8d 100644
--- a/VectoCore/VectoCore/Models/Simulation/Impl/SimulatorFactory.cs
+++ b/VectoCore/VectoCore/Models/Simulation/Impl/SimulatorFactory.cs
@@ -257,7 +257,8 @@ namespace TUGraz.VectoCore.Models.Simulation.Impl
 
 						var manStagesCount =
 							vifInputData.MultistageJobInputData.JobInputData.ManufacturingStages?.Count ?? 0;
-						(ReportWriter as FileOutputWriter).NumberOfManufacturingStages = manStagesCount;
+
+						ReportWriter.NumberOfManufacturingStages = manStagesCount;
 						var factory = new SimulatorFactory(_mode,
 							vifInputData, originalReportWriter,
 							null,
diff --git a/VectoCore/VectoCore/OutputData/FileIO/FileOutputWriter.cs b/VectoCore/VectoCore/OutputData/FileIO/FileOutputWriter.cs
index de26176d097d7766c3df5ab2cf218a6ee0ed5658..ece3596e1be9c053e190e2a7152badd623155aed 100644
--- a/VectoCore/VectoCore/OutputData/FileIO/FileOutputWriter.cs
+++ b/VectoCore/VectoCore/OutputData/FileIO/FileOutputWriter.cs
@@ -63,9 +63,8 @@ namespace TUGraz.VectoCore.OutputData.FileIO
 
 		private int? _numberOfManufacturingStages = null;
 
-		public int? NumberOfManufacturingStages
+		public int NumberOfManufacturingStages
 		{
-			get => _numberOfManufacturingStages;
 			set => _numberOfManufacturingStages = value;
 		}
 
diff --git a/VectoCore/VectoCore/OutputData/IDataWriter.cs b/VectoCore/VectoCore/OutputData/IDataWriter.cs
index 219622d15262779e25673c569caa640861f9cd2e..1ab43ecc3035b586d16ed586a4d61219dcc64373 100644
--- a/VectoCore/VectoCore/OutputData/IDataWriter.cs
+++ b/VectoCore/VectoCore/OutputData/IDataWriter.cs
@@ -60,6 +60,7 @@ namespace TUGraz.VectoCore.OutputData
 
 
 		IDictionary<ReportType, string> GetWrittenFiles();
+		int NumberOfManufacturingStages { set; }
 	}
 
 
diff --git a/VectoCore/VectoCoreTest/Integration/Declaration/NaturalGasVehicles.cs b/VectoCore/VectoCoreTest/Integration/Declaration/NaturalGasVehicles.cs
index 1d376873f14625dd106cfdcfee070e09f61a7b41..50a2fe0a411c5322d526211d8a0563c2d2a120fb 100644
--- a/VectoCore/VectoCoreTest/Integration/Declaration/NaturalGasVehicles.cs
+++ b/VectoCore/VectoCoreTest/Integration/Declaration/NaturalGasVehicles.cs
@@ -172,6 +172,11 @@ namespace TUGraz.VectoCore.Tests.Integration.Declaration
 			throw new NotImplementedException();
 		}
 
+		public int NumberOfManufacturingStages
+		{
+			set => throw new NotImplementedException();
+		}
+
 		#endregion
 
 		#region Implementation of ISummaryWriter