diff --git a/app/celery/reporting_tasks.py b/app/celery/reporting_tasks.py
index 960264fc6..f3cf640cf 100644
--- a/app/celery/reporting_tasks.py
+++ b/app/celery/reporting_tasks.py
@@ -84,15 +84,18 @@ def create_nightly_billing(day_start=None):
 
         for data in transit_data:
             update_count = FactBilling.query.filter(
-                FactBilling.bst_date == process_day,
+                FactBilling.bst_date == datetime.date(process_day),
                 FactBilling.template_id == data.template_id,
+                FactBilling.service_id == data.service_id,
                 FactBilling.provider == data.sent_by,  # This could be zero - this is a bug that needs to be fixed.
                 FactBilling.rate_multiplier == data.rate_multiplier,
                 FactBilling.notification_type == data.notification_type,
+                FactBilling.international == data.international
             ).update(
                 {"notifications_sent": data.notifications_sent,
                  "billable_units": data.billable_units},
                 synchronize_session=False)
+
             if update_count == 0:
                 billing_record = FactBilling(
                     bst_date=process_day,
diff --git a/tests/app/celery/test_reporting_tasks.py b/tests/app/celery/test_reporting_tasks.py
index b9ce112ec..9bf2daa99 100644
--- a/tests/app/celery/test_reporting_tasks.py
+++ b/tests/app/celery/test_reporting_tasks.py
@@ -404,3 +404,40 @@ def test_create_nightly_billing_use_BST(
     assert len(records) == 2
     assert records[0].bst_date == date(2018, 3, 25)
     assert records[-1].bst_date == date(2018, 3, 26)
+
+
+@freeze_time('2018-01-15T03:30:00')
+def test_create_nightly_billing_update_when_record_exists(
+        notify_db,
+        notify_db_session,
+        sample_service,
+        sample_template,
+        mocker):
+
+    mocker.patch('app.celery.reporting_tasks.get_rate', side_effect=mocker_get_rate)
+
+    sample_notification(
+        notify_db,
+        notify_db_session,
+        created_at=datetime.now() - timedelta(days=1),
+        service=sample_service,
+        template=sample_template,
+        status='delivered',
+        sent_by=None,
+        international=False,
+        rate_multiplier=1.0,
+        billable_units=1,
+    )
+
+    records = FactBilling.query.all()
+    assert len(records) == 0
+
+    create_nightly_billing()
+    records = FactBilling.query.order_by(FactBilling.bst_date).all()
+
+    assert len(records) == 1
+    assert records[0].bst_date == date(2018, 1, 14)
+
+    # run again, make sure create_nightly_billing() updates with no error
+    create_nightly_billing()
+    assert len(records) == 1