diff --git a/UID/Dienstplan/frmDiestAddMa.vb b/UID/Dienstplan/frmDiestAddMa.vb
index 4525796..64bf778 100644
--- a/UID/Dienstplan/frmDiestAddMa.vb
+++ b/UID/Dienstplan/frmDiestAddMa.vb
@@ -744,7 +744,7 @@ Public Class frmDiestAddMa
             If dgvAbwWStd.CurrentRow.Cells("dstaw_std").Value IsNot Nothing AndAlso IsNumeric(dgvAbwWStd.CurrentRow.Cells("dstaw_std").Value) Then
 
                 If Math.Floor(dgvAbwWStd.CurrentRow.Cells("dstaw_std").Value) <> 0 Then
-                    If dgvAbwWStd.CurrentRow.Cells("dstaw_std").Value Mod 1 <> 0.5 Then
+                    If dgvAbwWStd.CurrentRow.Cells("dstaw_std").Value Mod 1 <> 0.5 And dgvAbwWStd.CurrentRow.Cells("dstaw_std").Value Mod 1 <> 0 Then
                         MsgBox("Fehler, nur 0.5 als Nachkommastelle erlaubt")
                         btnOK.Enabled = False
                     Else