diff --git a/VectoCore/VectoCore/OutputData/XML/XMLMultistageBusReport.cs b/VectoCore/VectoCore/OutputData/XML/XMLMultistageBusReport.cs
index ce6de4a3804e55b595105358b2d5707265b7cc17..106ef6b5d02102fa977ed58382f0fc881e618764 100644
--- a/VectoCore/VectoCore/OutputData/XML/XMLMultistageBusReport.cs
+++ b/VectoCore/VectoCore/OutputData/XML/XMLMultistageBusReport.cs
@@ -277,10 +277,9 @@ namespace TUGraz.VectoCore.OutputData.XML
 			switch (_vehicleInputData.AirdragModifiedMultistage) {
 				case null:
 					throw new VectoException("AirdragModifiedMultistage must be set if an airdrag component has been set in previous stages.");
-				case false:
+				default:
 					return new XElement(v28 + XMLNames.Bus_AirdragModifiedMultistage, _vehicleInputData.AirdragModifiedMultistage);
 			}
-			return null;
 		}
 
 		private XElement GetADAS(IAdvancedDriverAssistantSystemDeclarationInputData adasData)
@@ -318,7 +317,7 @@ namespace TUGraz.VectoCore.OutputData.XML
 
 		private XElement GetBusAirdrag(IAirdragDeclarationInputData airdrag)
 		{
-			if (airdrag != null) 
+			if (airdrag != null && _vehicleInputData.AirdragModifiedMultistage != false) 
 				return GetAirdragElement(airdrag);
 
 			return _vehicleInputData.AirdragModifiedMultistage == true
diff --git a/VectoCore/VectoCoreTest/Integration/Multistage/MultistageVehicleTest.cs b/VectoCore/VectoCoreTest/Integration/Multistage/MultistageVehicleTest.cs
index 305c2a461dbb4837cff635618cc1f2ac3c462323..ed000eb7d38711d7a9c60e0cdecf0debe6f78020 100644
--- a/VectoCore/VectoCoreTest/Integration/Multistage/MultistageVehicleTest.cs
+++ b/VectoCore/VectoCoreTest/Integration/Multistage/MultistageVehicleTest.cs
@@ -346,7 +346,8 @@ namespace TUGraz.VectoCore.Tests.Integration.Multistage
 			Assert.IsTrue(progress.All(r => r.Value.Success), string.Concat<Exception>(progress.Select(r => r.Value.Error)));
 			Assert.IsTrue(jobContainer.Runs.All(r => r.Success), string.Concat<Exception>(jobContainer.Runs.Select(r => r.ExecException)));
 		}
-		
+
+		[NonParallelizable]
 		[TestCase(PrimaryBus, TestName = "Multistage Write VIF Primary"),
 		TestCase(PrimaryBus_SmartES, TestName = "Multistage Write VIF Primary SmartES")]
 		public void TestMultistageWritingVif(string primaryFile)
diff --git a/VectoCore/VectoCoreTest/TestData/XML/XMLReaderDeclaration/SchemaVersion2.8/vecto_vehicle-stage_input_full-sample.xml b/VectoCore/VectoCoreTest/TestData/XML/XMLReaderDeclaration/SchemaVersion2.8/vecto_vehicle-stage_input_full-sample.xml
index c417f3e1822ca5785ab51ec4db0b9a5ac6a00365..85f865e71925dbca4a77fc9246cadbfcf02df70b 100644
--- a/VectoCore/VectoCoreTest/TestData/XML/XMLReaderDeclaration/SchemaVersion2.8/vecto_vehicle-stage_input_full-sample.xml
+++ b/VectoCore/VectoCoreTest/TestData/XML/XMLReaderDeclaration/SchemaVersion2.8/vecto_vehicle-stage_input_full-sample.xml
@@ -15,7 +15,6 @@ xsi:schemaLocation="urn:tugraz:ivt:VectoAPI:DeclarationJob v:\VectoCore\VectoCor
 		<LegislativeCategory>M3</LegislativeCategory>
 		<CorrectedActualMass>500</CorrectedActualMass>
 		<TechnicalPermissibleMaximumLadenMass>3500</TechnicalPermissibleMaximumLadenMass>
-		<AirdragModifiedMultistage>false</AirdragModifiedMultistage>
 		<NgTankSystem>Compressed</NgTankSystem>
 		<ClassBus>II+III</ClassBus>
 		<NumberPassengerSeatsLowerDeck>1</NumberPassengerSeatsLowerDeck>
diff --git a/VectoCore/VectoCoreTest/XML/XMLMultistageBusInputDataTest.cs b/VectoCore/VectoCoreTest/XML/XMLMultistageBusInputDataTest.cs
index fa4c8b678a3b34567e2ea0e8a8120219f0b36004..2310a21f26852f99680f6a650ce4874d9db540d7 100644
--- a/VectoCore/VectoCoreTest/XML/XMLMultistageBusInputDataTest.cs
+++ b/VectoCore/VectoCoreTest/XML/XMLMultistageBusInputDataTest.cs
@@ -48,7 +48,7 @@ namespace TUGraz.VectoCore.Tests.XML
 			Assert.AreEqual(LegislativeClass.M3, vehicle.LegislativeClass);
 			Assert.AreEqual(500, vehicle.CurbMassChassis.Value());//CorrectedActualMass
 			Assert.AreEqual(3500, vehicle.GrossVehicleMassRating.Value());//TechnicalPermissibleMaximumLadenMass
-			Assert.AreEqual(false, vehicle.AirdragModifiedMultistage);
+			Assert.AreEqual(null, vehicle.AirdragModifiedMultistage);
 			Assert.AreEqual(TankSystem.Compressed, vehicle.TankSystem);//NgTankSystem
 			Assert.AreEqual(RegistrationClass.II_III, vehicle.RegisteredClass);//ClassBus
 			Assert.AreEqual(1, vehicle.NumberPassengerSeatsLowerDeck);