diff --git a/src/ifcopenshell-python/ifcopenshell/api/constraint/add_metric.py b/src/ifcopenshell-python/ifcopenshell/api/constraint/add_metric.py
index 8619b32acb..2941eb8308 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/constraint/add_metric.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/constraint/add_metric.py
@@ -58,4 +58,5 @@ class Usecase:
         if self.settings["objective"]:
             benchmark_values = list(self.settings["objective"].BenchmarkValues or [])
             benchmark_values.append(metric)
+            self.settings["objective"].BenchmarkValues = benchmark_values
         return metric