diff --git a/src/libslic3r/GCode.cpp b/src/libslic3r/GCode.cpp
index c2db414fc5..d29363e639 100644
--- a/src/libslic3r/GCode.cpp
+++ b/src/libslic3r/GCode.cpp
@@ -3173,8 +3173,8 @@ void GCode::_do_export(Print& print, GCodeOutputStream &file, ThumbnailsGenerato
     if (print.config().belt_printer.value) {
         m_writer.set_first_layer_point_test([this](const Vec3d &point_logical) {
             const Vec2d extruder_offset = m_writer.filament() != nullptr ? EXTRUDER_CONFIG(extruder_offset) : Vec2d::Zero();
-            // The writer hands over the point with the plate origin (its XY offset) already
-            // taken off, while m_origin still carries it: take off the instance part only.
+            // Undo what point_to_gcode() added (m_origin, minus the extruder offset) and
+            // what the writer then took off (its XY offset, the plate origin).
             const Vec2d plate_offset = m_writer.get_xy_offset().cast<double>();
             return this->on_first_layer(Vec3d(point_logical.x() - (m_origin.x() - plate_offset.x()) + extruder_offset.x(),
                                               point_logical.y() - (m_origin.y() - plate_offset.y()) + extruder_offset.y(),