diff --git a/Kernel/System/Calendar/Appointment.pm b/Kernel/System/Calendar/Appointment.pm
index 2a134743fe6..b40c6928fc4 100644
--- a/Kernel/System/Calendar/Appointment.pm
+++ b/Kernel/System/Calendar/Appointment.pm
@@ -2376,8 +2376,8 @@ sub _AppointmentRecurringCreate {
             my $EndDSTDiff = $EndTimeObject->CompareDST($OriginalEndTimeObject);
             my $CurrentStartTimeObject = $StartTimeObject->Clone();
             my $CurrentEndTimeObject   = $EndTimeObject->Clone();
-            if ( $StartDSTDiff ) {
-                if ( IsPositiveInteger($StartDSTDiff) ) {
+            if ( IsInteger( $StartDSTDiff ) ) {
+                if ( $StartDSTDiff > 0 ) {
                     $CurrentStartTimeObject->Subtract( Seconds => $StartDSTDiff );
                 }
                 elsif ( $StartDSTDiff < 0 ) {
@@ -2385,8 +2385,8 @@ sub _AppointmentRecurringCreate {
                 }
                 $StartTime = $CurrentStartTimeObject->ToString();
             }
-            if ( $EndDSTDiff ) {
-                if ( IsPositiveInteger($EndDSTDiff) ) {
+            if ( IsInteger($EndDSTDiff) ) {
+                if ( $EndDSTDiff > 0 ) {
                     $CurrentEndTimeObject->Subtract( Seconds => $EndDSTDiff );
                 }
                 elsif ( $EndDSTDiff < 0 ) {
diff --git a/Kernel/System/DateTime.pm b/Kernel/System/DateTime.pm
index b7adb635727..9c4fc3603ec 100644
--- a/Kernel/System/DateTime.pm
+++ b/Kernel/System/DateTime.pm
@@ -2242,9 +2242,7 @@ sub _OpNotEquals {
 
 sub CompareDST {
     my ($Self, $OtherDateTimeObject) = @_;
-    my $TimeDif = $Self->{CPANDateTimeObject}->offset - $OtherDateTimeObject->{CPANDateTimeObject}->offset;
-
-    return $TimeDif;
+    return $Self->{CPANDateTimeObject}->offset - $OtherDateTimeObject->{CPANDateTimeObject}->offset;
 }
 1;