diff --git a/app/main/views/dashboard.py b/app/main/views/dashboard.py
index e29727536..9cbeba214 100644
--- a/app/main/views/dashboard.py
+++ b/app/main/views/dashboard.py
@@ -442,7 +442,7 @@ def format_letter_details_for_month(letter_units_for_month):
         rate_group = list(rate_group)
 
         letter_details = LetterDetails(
-            sent=sum(x['billing_units'] for x in rate_group),
+            sent=sum(x['notifications_sent'] for x in rate_group),
             rate=rate_group[0]['rate'],
             cost=sum(x['letter_cost'] for x in rate_group),
             postage_description=rate_group[0]['postage']
diff --git a/tests/app/main/views/test_dashboard.py b/tests/app/main/views/test_dashboard.py
index 1a47d4ced..2e48c1291 100644
--- a/tests/app/main/views/test_dashboard.py
+++ b/tests/app/main/views/test_dashboard.py
@@ -1106,7 +1106,8 @@ def test_usage_page_displays_letters_ordered_by_postage(
             'month': 'April',
             'notification_type': 'letter',
             'rate': 0.5,
-            'billing_units': 1,
+            'chargeable_units': 1,
+            'notifications_sent': 1,
             'postage': 'second',
             'letter_cost': 0.5,
         },
@@ -1114,7 +1115,8 @@ def test_usage_page_displays_letters_ordered_by_postage(
             'month': 'April',
             'notification_type': 'letter',
             'rate': 1,
-            'billing_units': 1,
+            'chargeable_units': 1,
+            'notifications_sent': 1,
             'postage': 'europe',
             'letter_cost': 1,
         },
@@ -1122,7 +1124,8 @@ def test_usage_page_displays_letters_ordered_by_postage(
             'month': 'April',
             'notification_type': 'letter',
             'rate': 1,
-            'billing_units': 2,
+            'chargeable_units': 2,
+            'notifications_sent': 2,
             'postage': 'rest-of-word',
             'letter_cost': 2,
         },
@@ -1130,7 +1133,8 @@ def test_usage_page_displays_letters_ordered_by_postage(
             'month': 'April',
             'notification_type': 'letter',
             'rate': 1.5,
-            'billing_units': 7,
+            'chargeable_units': 7,
+            'notifications_sent': 7,
             'postage': 'europe',
             'letter_cost': 11.5,
         },
@@ -1138,7 +1142,8 @@ def test_usage_page_displays_letters_ordered_by_postage(
             'month': 'April',
             'notification_type': 'letter',
             'rate': 0.3,
-            'billing_units': 3,
+            'chargeable_units': 3,
+            'notifications_sent': 3,
             'postage': 'second',
             'letter_cost': 0.9,
         },
@@ -1146,7 +1151,8 @@ def test_usage_page_displays_letters_ordered_by_postage(
             'month': 'April',
             'notification_type': 'letter',
             'rate': 0.5,
-            'billing_units': 1,
+            'chargeable_units': 1,
+            'notifications_sent': 1,
             'postage': 'first',
             'letter_cost': 0.5,
         },
@@ -1183,7 +1189,8 @@ def test_usage_page_displays_letters_split_by_month_and_postage(
             'month': 'April',
             'notification_type': 'letter',
             'rate': 0.5,
-            'billing_units': 1,
+            'chargeable_units': 1,
+            'notifications_sent': 1,
             'postage': 'second',
             'letter_cost': 0.5,
         },
@@ -1191,7 +1198,8 @@ def test_usage_page_displays_letters_split_by_month_and_postage(
             'month': 'April',
             'notification_type': 'letter',
             'rate': 1,
-            'billing_units': 1,
+            'chargeable_units': 1,
+            'notifications_sent': 1,
             'postage': 'europe',
             'letter_cost': 1,
         },
@@ -1199,7 +1207,8 @@ def test_usage_page_displays_letters_split_by_month_and_postage(
             'month': 'May',
             'notification_type': 'letter',
             'rate': 1,
-            'billing_units': 7,
+            'chargeable_units': 7,
+            'notifications_sent': 7,
             'postage': 'europe',
             'letter_cost': 7,
         },
@@ -1207,7 +1216,8 @@ def test_usage_page_displays_letters_split_by_month_and_postage(
             'month': 'May',
             'notification_type': 'letter',
             'rate': 0.5,
-            'billing_units': 3,
+            'chargeable_units': 3,
+            'notifications_sent': 3,
             'postage': 'second',
             'letter_cost': 1.5,
         },
@@ -1215,7 +1225,8 @@ def test_usage_page_displays_letters_split_by_month_and_postage(
             'month': 'May',
             'notification_type': 'letter',
             'rate': 0.7,
-            'billing_units': 1,
+            'chargeable_units': 1,
+            'notifications_sent': 1,
             'postage': 'first',
             'letter_cost': 0.7,
         },
@@ -1665,7 +1676,8 @@ def test_get_monthly_usage_breakdown(now, expected_number_of_months):
                 'rate_multiplier': 1,
                 'notification_type': 'sms',
                 'rate': 1.65,
-                'billing_units': 100000,
+                'chargeable_units': 100000,
+                'notifications_sent': 1234,
                 'sms_charged': 0,
                 'sms_free_allowance_used': 100000,
                 'sms_cost': 0,
@@ -1676,7 +1688,8 @@ def test_get_monthly_usage_breakdown(now, expected_number_of_months):
                 'rate_multiplier': 1,
                 'notification_type': 'sms',
                 'rate': 1.65,
-                'billing_units': 100000,
+                'chargeable_units': 100000,
+                'notifications_sent': 1234,
                 'sms_charged': 0,
                 'sms_free_allowance_used': 100000,
                 'sms_cost': 0,
@@ -1687,7 +1700,8 @@ def test_get_monthly_usage_breakdown(now, expected_number_of_months):
                 'rate_multiplier': 1,
                 'notification_type': 'sms',
                 'rate': 1.71,
-                'billing_units': 100000,
+                'chargeable_units': 100000,
+                'notifications_sent': 1234,
                 'sms_charged': 50000,
                 'sms_free_allowance_used': 50000,
                 'sms_cost': 85500,
@@ -1698,7 +1712,8 @@ def test_get_monthly_usage_breakdown(now, expected_number_of_months):
                 'rate_multiplier': 1,
                 'notification_type': 'sms',
                 'rate': 1.71,
-                'billing_units': 2000,
+                'chargeable_units': 2000,
+                'notifications_sent': 1234,
                 'sms_charged': 2000,
                 'sms_free_allowance_used': 0,
                 'sms_cost': 3420,
diff --git a/tests/conftest.py b/tests/conftest.py
index 388805cc5..1ae650b5a 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -2362,7 +2362,8 @@ def mock_get_monthly_usage_for_service(mocker):
                 'month': 'March',
                 'notification_type': 'sms',
                 'rate': 0.017,
-                'billing_units': 1230,
+                'chargeable_units': 1230,
+                'notifications_sent': 1234,
                 'postage': 'none',
                 'sms_charged': 1230,
                 'sms_free_allowance_used': 0,
@@ -2373,7 +2374,8 @@ def mock_get_monthly_usage_for_service(mocker):
                 'month': 'February',
                 'notification_type': 'sms',
                 'rate': 0.0165,
-                'billing_units': 1100,
+                'chargeable_units': 1100,
+                'notifications_sent': 1234,
                 'postage': 'none',
                 'sms_charged': 960,
                 'sms_free_allowance_used': 140,
@@ -2384,7 +2386,8 @@ def mock_get_monthly_usage_for_service(mocker):
                 'month': 'February',
                 'notification_type': 'letter',
                 'rate': 0.31,
-                'billing_units': 10,
+                'chargeable_units': 10,
+                'notifications_sent': 10,
                 'postage': 'second',
                 'sms_charged': 0,
                 'sms_free_allowance_used': 0,
@@ -2395,7 +2398,8 @@ def mock_get_monthly_usage_for_service(mocker):
                 'month': 'February',
                 'notification_type': 'letter',
                 'rate': 0.33,
-                'billing_units': 5,
+                'chargeable_units': 5,
+                'notifications_sent': 5,
                 'postage': 'first',
                 'sms_charged': 0,
                 'sms_free_allowance_used': 0,
@@ -2406,7 +2410,8 @@ def mock_get_monthly_usage_for_service(mocker):
                 'month': 'February',
                 'notification_type': 'letter',
                 'rate': 0.84,
-                'billing_units': 3,
+                'chargeable_units': 3,
+                'notifications_sent': 3,
                 'postage': 'europe',
                 'sms_charged': 0,
                 'sms_free_allowance_used': 0,
@@ -2417,7 +2422,8 @@ def mock_get_monthly_usage_for_service(mocker):
                 'month': 'February',
                 'notification_type': 'letter',
                 'rate': 0.84,
-                'billing_units': 7,
+                'chargeable_units': 7,
+                'notifications_sent': 7,
                 'postage': 'rest-of-world',
                 'sms_charged': 0,
                 'sms_free_allowance_used': 0,
@@ -2428,7 +2434,8 @@ def mock_get_monthly_usage_for_service(mocker):
                 'month': 'April',
                 'notification_type': 'sms',
                 'rate': 0.017,
-                'billing_units': 249860,
+                'chargeable_units': 249860,
+                'notifications_sent': 1234,
                 'postage': 'none',
                 'sms_charged': 0,
                 'sms_free_allowance_used': 249860,