diff --git a/metrics_utility/automation_controller_billing/dataframe_engine/dataframe_jobhost_summary_usage.py b/metrics_utility/automation_controller_billing/dataframe_engine/dataframe_jobhost_summary_usage.py
index 4fd174c..fb98c29 100644
--- a/metrics_utility/automation_controller_billing/dataframe_engine/dataframe_jobhost_summary_usage.py
+++ b/metrics_utility/automation_controller_billing/dataframe_engine/dataframe_jobhost_summary_usage.py
@@ -54,8 +54,8 @@ def sum_columns(row):
                     billing_data['job_created'] = pd.to_datetime(
                         billing_data['job_created']).dt.tz_localize(None)
                 else:
-                    billing_data['job_created'] = ''
-                    
+                    billing_data['job_created'] = pd.NaT
+
                 ################################
                 # Do the aggregation
                 ################################