diff --git a/src/libslic3r/Config.cpp b/src/libslic3r/Config.cpp
index ec5699e98..188a2e7ea 100644
--- a/src/libslic3r/Config.cpp
+++ b/src/libslic3r/Config.cpp
@@ -711,7 +711,8 @@ double ConfigBase::get_abs_value(const t_config_option_key &opt_key) const
         return opt_def->ratio_over.empty() ? 0. :
             static_cast<const ConfigOptionFloatOrPercent*>(raw_opt)->get_abs_value(this->get_abs_value(opt_def->ratio_over));
     }
-    throw ConfigurationError("ConfigBase::get_abs_value(): Not a valid option type for get_abs_value()");
+    std::string err_info = "ConfigBase::get_abs_value(): Not a valid option type for get_abs_value(), parameter : " + opt_key;
+    throw ConfigurationError(err_info);
 }
 
 // Return an absolute value of a possibly relative config variable.
diff --git a/src/libslic3r/GCode.cpp b/src/libslic3r/GCode.cpp
index 47b4259b5..9069b6fd6 100644
--- a/src/libslic3r/GCode.cpp
+++ b/src/libslic3r/GCode.cpp
@@ -4937,7 +4937,7 @@ std::string GCode::_extrude(const ExtrusionPath &path, std::string description,
                 speed = new_speed == 0.0 ? speed : new_speed;
             }
         } else if (path.role() == erOverhangPerimeter && path.overhang_degree == 5) {
-            speed = m_config.get_abs_value("overhang_totally_speed");
+            speed = m_config.overhang_totally_speed.get_at(cur_extruder_index());
         } else if (path.role() == erOverhangPerimeter || path.role() == erBridgeInfill || path.role() == erSupportTransition) {
             speed = m_config.bridge_speed.get_at(cur_extruder_index());
         } else if (path.role() == erInternalInfill) {