diff --git a/src/MissionManager/StructureScanComplexItem.cc b/src/MissionManager/StructureScanComplexItem.cc
index c9a2fc1a34dff31539659ebbb30506797021fefb..100896efbbf25459e7bace94f60ba1ccfad231bf 100644
--- a/src/MissionManager/StructureScanComplexItem.cc
+++ b/src/MissionManager/StructureScanComplexItem.cc
@@ -63,9 +63,11 @@ StructureScanComplexItem::StructureScanComplexItem(Vehicle* vehicle, bool flyVie
     connect(&_altitudeFact, &Fact::valueChanged, this, &StructureScanComplexItem::_updateCoordinateAltitudes);
 
     connect(&_structurePolygon, &QGCMapPolygon::dirtyChanged,   this, &StructureScanComplexItem::_polygonDirtyChanged);
-    connect(&_structurePolygon, &QGCMapPolygon::countChanged,   this, &StructureScanComplexItem::_polygonCountChanged);
     connect(&_structurePolygon, &QGCMapPolygon::pathChanged,    this, &StructureScanComplexItem::_rebuildFlightPolygon);
 
+    connect(&_structurePolygon, &QGCMapPolygon::countChanged,   this, &StructureScanComplexItem::_updateLastSequenceNumber);
+    connect(&_layersFact,       &Fact::valueChanged,            this, &StructureScanComplexItem::_updateLastSequenceNumber);
+
     connect(&_flightPolygon,    &QGCMapPolygon::pathChanged,    this, &StructureScanComplexItem::_flightPathChanged);
 
     connect(_cameraCalc.distanceToSurface(),    &Fact::valueChanged,                this, &StructureScanComplexItem::_rebuildFlightPolygon);
@@ -108,19 +110,23 @@ void StructureScanComplexItem::_clearInternal(void)
     emit lastSequenceNumberChanged(lastSequenceNumber());
 }
 
-void StructureScanComplexItem::_polygonCountChanged(int count)
+void StructureScanComplexItem::_updateLastSequenceNumber(void)
 {
-    Q_UNUSED(count);
     emit lastSequenceNumberChanged(lastSequenceNumber());
 }
 
 int StructureScanComplexItem::lastSequenceNumber(void) const
 {
-    return _sequenceNumber +
-            (_layersFact.rawValue().toInt() *
-             ((_flightPolygon.count() + 1) +    // 1 waypoint for each polygon vertex + 1 to go back to first polygon vertex for each layer
-              2)) +                             // Camera trigger start/stop for each layer
-            2;                                  // ROI_WPNEXT_OFFSET and ROI_NONE commands
+    // Each structure layer contains:
+    //  1 waypoint for each polygon vertex + 1 to go back to first polygon vertex for each layer
+    //  Two commands for camera trigger start/stop
+    int layerItemCount = _flightPolygon.count() + 1 + 2;
+
+    int multiLayerItemCount = layerItemCount * _layersFact.rawValue().toInt();
+
+    int itemCount = multiLayerItemCount + 2;    // +2 for ROI_WPNEXT_OFFSET and ROI_NONE commands
+
+    return _sequenceNumber + itemCount - 1;
 }
 
 void StructureScanComplexItem::setDirty(bool dirty)
diff --git a/src/MissionManager/StructureScanComplexItem.h b/src/MissionManager/StructureScanComplexItem.h
index 904f57e4c3c1bc9cacc6f3035705863d949a89c4..068b8a40645ef83215c3068d53c079ae3075d006 100644
--- a/src/MissionManager/StructureScanComplexItem.h
+++ b/src/MissionManager/StructureScanComplexItem.h
@@ -107,13 +107,13 @@ signals:
 private slots:
     void _setDirty(void);
     void _polygonDirtyChanged       (bool dirty);
-    void _polygonCountChanged       (int count);
     void _flightPathChanged         (void);
     void _clearInternal             (void);
     void _updateCoordinateAltitudes (void);
     void _rebuildFlightPolygon      (void);
     void _recalcCameraShots         (void);
     void _recalcLayerInfo           (void);
+    void _updateLastSequenceNumber  (void);
 
 private:
     void _setExitCoordinate(const QGeoCoordinate& coordinate);
diff --git a/src/MissionManager/StructureScanComplexItemTest.cc b/src/MissionManager/StructureScanComplexItemTest.cc
index 13b0173ac1b30057f457bdbbaa88bd036c8c3d7b..88352c9add74b678cee083f0a60eb2731c44c574 100644
--- a/src/MissionManager/StructureScanComplexItemTest.cc
+++ b/src/MissionManager/StructureScanComplexItemTest.cc
@@ -134,6 +134,6 @@ void StructureScanComplexItemTest::_testItemCount(void)
 
     _initItem();
     _structureScanItem->appendMissionItems(items, this);
-    QCOMPARE(items.count(), _structureScanItem->lastSequenceNumber());
+    QCOMPARE(items.count() - 1, _structureScanItem->lastSequenceNumber());
 
 }