diff --git a/TestFlightContracts/TestFlightContractConfigurator.cs b/TestFlightContracts/TestFlightContractConfigurator.cs
index 3ceff57..28dd7a4 100644
--- a/TestFlightContracts/TestFlightContractConfigurator.cs
+++ b/TestFlightContracts/TestFlightContractConfigurator.cs
@@ -82,13 +82,13 @@ protected override void OnParameterLoad(ConfigNode node)
         protected override void OnRegister()
         {
             base.OnRegister();
-            GameEvents.Contract.onAccepted.Add(new EventData<Contract>.OnEvent(OnContractAccepted));
+            GameEvents.Contract.onAccepted.Add(OnContractAccepted);
         }
 
         protected override void OnUnregister()
         {
             base.OnUnregister();
-            GameEvents.Contract.onAccepted.Remove(new EventData<Contract>.OnEvent(OnContractAccepted));
+            GameEvents.Contract.onAccepted.Remove(OnContractAccepted);
         }
 
         protected void OnContractAccepted(Contract contract)
diff --git a/TestFlightCore/TestFlightCore/TestFlight.cs b/TestFlightCore/TestFlightCore/TestFlight.cs
index c49cf4c..c6c9edc 100644
--- a/TestFlightCore/TestFlightCore/TestFlight.cs
+++ b/TestFlightCore/TestFlightCore/TestFlight.cs
@@ -405,8 +405,10 @@ public class TestFlightManagerScenario : ScenarioModule
 
         [KSPField(isPersistant = true)] public bool settingsEnabled = true;
         [KSPField(isPersistant = true)] public bool settingsAlwaysMaxData = false;
+        [KSPField(isPersistant = true)] public bool settingsTechDiscountEnabled = false;
         public bool SettingsEnabled { get { return settingsEnabled; } set { settingsEnabled = value; } }
         public bool SettingsAlwaysMaxData { get { return settingsAlwaysMaxData; } set { settingsAlwaysMaxData = value; } }
+        public bool SettingsTechDiscountEnabled { get { return settingsTechDiscountEnabled; } set { settingsTechDiscountEnabled = value; } }
 
         private bool rp1Available = false;
         private bool careerLogging = false;
diff --git a/TestFlightCore/TestFlightCore/TestFlightCore.cs b/TestFlightCore/TestFlightCore/TestFlightCore.cs
index cf5eedb..786276f 100644
--- a/TestFlightCore/TestFlightCore/TestFlightCore.cs
+++ b/TestFlightCore/TestFlightCore/TestFlightCore.cs
@@ -803,11 +803,8 @@ public override void Start()
         public override void OnDestroy()
         {
             base.OnDestroy();
-            if (HighLogic.LoadedSceneIsFlight)
-            {
-                GameEvents.onCrewTransferred.Remove(OnCrewChange);
-                GameEvents.onStageActivate.Remove(OnStageActivate);
-            }
+            GameEvents.onCrewTransferred.Remove(OnCrewChange);
+            GameEvents.onStageActivate.Remove(OnStageActivate);
         }
 
         public override void OnAwake()
diff --git a/TestFlightCore/TestFlightCore/TestFlightKSC.cs b/TestFlightCore/TestFlightCore/TestFlightKSC.cs
index 561505b..90885f1 100644
--- a/TestFlightCore/TestFlightCore/TestFlightKSC.cs
+++ b/TestFlightCore/TestFlightCore/TestFlightKSC.cs
@@ -308,6 +308,13 @@ internal override void DrawWindow(int id)
                                 tfScenario.SettingsAlwaysMaxData = saveMaxData;
                             }
                             GUILayout.EndHorizontal();
+                            GUILayout.BeginHorizontal();
+                            bool techDiscountEnabled = tfScenario.SettingsTechDiscountEnabled;
+                            if (DrawToggle(ref techDiscountEnabled, "Apply discount to tech node cost for flown parts", Styles.styleToggle))
+                            {
+                                tfScenario.SettingsTechDiscountEnabled = techDiscountEnabled;
+                            }
+                            GUILayout.EndHorizontal();
                             break;
                     }
                     break;
diff --git a/TestFlightCore/TestFlightCore/TestFlightRnD.cs b/TestFlightCore/TestFlightCore/TestFlightRnD.cs
index 01c40eb..f8c5429 100644
--- a/TestFlightCore/TestFlightCore/TestFlightRnD.cs
+++ b/TestFlightCore/TestFlightCore/TestFlightRnD.cs
@@ -13,14 +13,17 @@ namespace TestFlightCore
     public class TestFlightRnD : MonoBehaviour
     {
         Dictionary<string, int> baseCost = null;
+
         public void Start()
         {
-            RDController.OnRDTreeSpawn.Add(new EventData<RDController>.OnEvent(OnTreeSpawn));
+            RDController.OnRDTreeSpawn.Add(OnTreeSpawn);
             DontDestroyOnLoad(this);
         }
+
         public void OnTreeSpawn(RDController controller)
         {
-            if (TestFlightManagerScenario.Instance == null || controller.nodes == null)
+            if (TestFlightManagerScenario.Instance == null || controller.nodes == null ||
+                !TestFlightManagerScenario.Instance.SettingsTechDiscountEnabled)
             {
                 return;
             }