diff --git a/ReportImp/LyvieKupfer/ServiceInvoiceReport.cs b/ReportImp/LyvieKupfer/ServiceInvoiceReport.cs
index 71e3e4941..6a61f0ebd 100644
--- a/ReportImp/LyvieKupfer/ServiceInvoiceReport.cs
+++ b/ReportImp/LyvieKupfer/ServiceInvoiceReport.cs
@@ -28,7 +28,7 @@ namespace LyvieKupfer
                     {
                         foreach (var ii in sip.ServiceInvoiceItems)
                         {
-                            hours = ii.Hours.Value;
+                            hours += ii.Hours.Value;
                         }
                     }
                 }