diff --git a/Elwig/Helpers/Billing/BillingData.cs b/Elwig/Helpers/Billing/BillingData.cs
index fb94b4b..7992800 100644
--- a/Elwig/Helpers/Billing/BillingData.cs
+++ b/Elwig/Helpers/Billing/BillingData.cs
@@ -367,7 +367,7 @@ namespace Elwig.Helpers.Billing {
             }
             if (qualityWei.Count == 1) {
                 data["quality"] = new JsonObject() {
-                    ["WEI"] = qualityWei.Single().Value
+                    ["WEI"] = qualityWei.Single().Value?.DeepClone()
                 };
             } else if (qualityWei.Count > 1) {
                 data["quality"] = new JsonObject() {
diff --git a/Elwig/Helpers/Billing/EditBillingData.cs b/Elwig/Helpers/Billing/EditBillingData.cs
index ac6bce9..643641e 100644
--- a/Elwig/Helpers/Billing/EditBillingData.cs
+++ b/Elwig/Helpers/Billing/EditBillingData.cs
@@ -42,7 +42,7 @@ namespace Elwig.Helpers.Billing {
                 dict2[idx].Add("default");
             }
 
-            var virtOffset = dict1.Max(e => e.Key) + 1;
+            var virtOffset = dict1.Count > 0 ? dict1.Max(e => e.Key) + 1 : 1;
             Dictionary<int, Curve> curves = GetCurves();
             decimal[] virtCurves = [.. dict2.Keys.Order()];
             for (int i = 0; i < virtCurves.Length; i++) {
diff --git a/Elwig/Windows/ChartWindow.xaml b/Elwig/Windows/ChartWindow.xaml
index 5b18c3a..1c75004 100644
--- a/Elwig/Windows/ChartWindow.xaml
+++ b/Elwig/Windows/ChartWindow.xaml
@@ -60,7 +60,7 @@
                 <ColumnDefinition Width="100"/>
             </Grid.ColumnDefinitions>
 
-            <Label Content="Für:" Margin="10,0,0,0" FontSize="14" Grid.Column="0" VerticalAlignment="Center"/>
+            <Label Content="Für:" Margin="10,-2,0,0" FontSize="14" Grid.Column="0" VerticalAlignment="Center"/>
             <xctk:CheckComboBox x:Name="ContractInput" Margin="50,0,0,0" Grid.Column="0"
                                 Delimiter=", " AllItemsSelectedContent="Alle" IsEnabled="False" ItemSelectionChanged="ContractInput_Changed"
                                 Width="500" Height="25" HorizontalAlignment="Left">
@@ -134,41 +134,30 @@
                 </Grid>
             </GroupBox>
 
-            <GroupBox Header="Gebunden" Grid.Row="1" Margin="0,5,5,5">
+            <GroupBox Header="Gebunden Aufschlag" Grid.Row="1" Margin="0,5,5,5">
                 <Grid>
-                    <Grid.ColumnDefinitions>
-                        <ColumnDefinition Width="85"/>
-                        <ColumnDefinition Width="*"/>
-                    </Grid.ColumnDefinitions>
 
                     <StackPanel Margin="10,10,0,0">
                         <RadioButton x:Name="GebundenTypeFixed" GroupName="GebundenType" Checked="GebundenType_Checked" IsEnabled="False">Fix</RadioButton>
-                        <RadioButton x:Name="GebundenTypeGraph" GroupName="GebundenType" Checked="GebundenType_Checked" IsEnabled="False">Graph</RadioButton>
+                        <RadioButton x:Name="GebundenTypeGraph" GroupName="GebundenType" Checked="GebundenType_Checked" IsEnabled="False">Frei</RadioButton>
                         <RadioButton x:Name="GebundenTypeNone" GroupName="GebundenType" Checked="GebundenType_Checked" IsEnabled="False">Nein</RadioButton>
                     </StackPanel>
 
                     <ctrl:UnitTextBox x:Name="GebundenFlatBonus" Unit="€/kg" TextChanged="GebundenFlatBonus_TextChanged" IsEnabled="False"
-                                      Width="90" Margin="0,5,0,0" HorizontalAlignment="Left" VerticalAlignment="Top" Grid.Column="1"/>
+                                      Width="90" Margin="5,5,5,5" HorizontalAlignment="Right" VerticalAlignment="Top" Grid.Column="1"/>
                 </Grid>
             </GroupBox>
 
             <GroupBox Header="Aktionen" Grid.Row="2" Margin="0,5,5,5">
                 <Grid>
-                    <Grid.ColumnDefinitions>
-                        <ColumnDefinition Width="*"/>
-                    </Grid.ColumnDefinitions>
-
                     <Button x:Name="LeftFlatButton" Content="Links flach" Click="LeftFlatButton_Click" IsEnabled="False"
                             HorizontalAlignment="Stretch" VerticalAlignment="Top" Margin="10,10,10,10"/>
-
                     <Button x:Name="RightFlatButton" Content="Rechts flach" Click="RightFlatButton_Click" IsEnabled="False"
-                            HorizontalAlignment="Stretch" VerticalAlignment="Top" Margin="10,50,10,10"/>
-
+                            HorizontalAlignment="Stretch" VerticalAlignment="Top" Margin="10,45,10,10"/>
                     <Button x:Name="InterpolateButton" Content="Interpolieren" Click="InterpolateButton_Click" IsEnabled="False"
-                            HorizontalAlignment="Stretch" VerticalAlignment="Top" Margin="10,90,10,10"/>
-
+                            HorizontalAlignment="Stretch" VerticalAlignment="Top" Margin="10,80,10,10"/>
                     <Button x:Name="LinearIncreaseButton" Content="Linear wachsen" Click="LinearIncreaseButton_Click" IsEnabled="False"
-                            HorizontalAlignment="Stretch" VerticalAlignment="Top" Margin="10,130,10,10"/>
+                            HorizontalAlignment="Stretch" VerticalAlignment="Top" Margin="10,115,10,10"/>
                 </Grid>
             </GroupBox>