diff --git a/ack_backend/src/update_ack_file.py b/ack_backend/src/update_ack_file.py
index 3c791a107..0b73a9037 100644
--- a/ack_backend/src/update_ack_file.py
+++ b/ack_backend/src/update_ack_file.py
@@ -108,7 +108,7 @@ def upload_ack_file(
             "file_key": file_key,
             "supplier": supplier,
             "vaccine_type": vaccine_type,
-            "row_count": row_count_source,
+            "row_count": row_count_source - 1,
         }
     else:
         result = None
diff --git a/ack_backend/tests/utils/values_for_ack_backend_tests.py b/ack_backend/tests/utils/values_for_ack_backend_tests.py
index 84e686ee7..0e898a2ff 100644
--- a/ack_backend/tests/utils/values_for_ack_backend_tests.py
+++ b/ack_backend/tests/utils/values_for_ack_backend_tests.py
@@ -227,7 +227,7 @@ class ValidValues:
         "file_key": MOCK_MESSAGE_DETAILS.file_key,
         "vaccine_type": MOCK_MESSAGE_DETAILS.vaccine_type,
         "message_id": MOCK_MESSAGE_DETAILS.row_id,
-        "row_count": 100,
+        "row_count": 99,
         "statusCode": 200,
         "message": "Record processing complete",
     }