diff --git a/core/tests/test_user.py b/core/tests/test_user.py
index c767f3f4..0fdf43c9 100644
--- a/core/tests/test_user.py
+++ b/core/tests/test_user.py
@@ -158,10 +158,11 @@ def test_user_invoice_with_multiple_items():
     item_recipe = Recipe(InvoiceItem, invoice=foreign_key(Recipe(Invoice, user=user)))
     item_recipe.make(_quantity=3, quantity=1, product_unit_price=5)
     item_recipe.make(_quantity=1, quantity=1, product_unit_price=5)
+    item_recipe.make(_quantity=2, quantity=1, product_unit_price=iter([5, 8]))
     res = list(
         Invoice.objects.filter(user=user)
         .annotate_total()
         .order_by("-total")
         .values_list("total", flat=True)
     )
-    assert res == [15, 5]
+    assert res == [15, 13, 5]
diff --git a/core/views/user.py b/core/views/user.py
index 286a3a92..027a7edc 100644
--- a/core/views/user.py
+++ b/core/views/user.py
@@ -21,9 +21,11 @@
 # Place - Suite 330, Boston, MA 02111-1307, USA.
 #
 #
+import itertools
 
 # This file contains all the views that concern the user model
 from datetime import date, timedelta
+from operator import itemgetter
 from smtplib import SMTPException
 
 from django.conf import settings
@@ -665,9 +667,15 @@ class UserAccountView(UserAccountBase):
         kwargs["refilling_month"] = self.expense_by_month(
             Refilling.objects.filter(customer=self.object.customer)
         )
-        kwargs["invoices_month"] = self.expense_by_month(
-            Invoice.objects.filter(user=self.object)
-        )
+        kwargs["invoices_month"] = [
+            # the django ORM removes the `group by` clause in this query,
+            # so a little of post-processing is needed
+            {"grouped_date": key, "total": sum(i["total"] for i in group)}
+            for key, group in itertools.groupby(
+                self.expense_by_month(Invoice.objects.filter(user=self.object)),
+                key=itemgetter("grouped_date"),
+            )
+        ]
         kwargs["etickets"] = self.object.customer.buyings.exclude(product__eticket=None)
         return kwargs
 
diff --git a/eboutic/models.py b/eboutic/models.py
index 468562ad..7ec9deef 100644
--- a/eboutic/models.py
+++ b/eboutic/models.py
@@ -173,9 +173,8 @@ class InvoiceQueryset(models.QuerySet):
         return self.annotate(
             total=Subquery(
                 InvoiceItem.objects.filter(invoice_id=OuterRef("pk"))
-                .annotate(item_amount=F("product_unit_price") * F("quantity"))
-                .values("item_amount")
-                .annotate(total=Sum("item_amount"))
+                .values("invoice_id")
+                .annotate(total=Sum(F("product_unit_price") * F("quantity")))
                 .values("total")
             )
         )