diff --git a/membershipworks/models.py b/membershipworks/models.py
index caf7acb..94a54c5 100644
--- a/membershipworks/models.py
+++ b/membershipworks/models.py
@@ -415,13 +415,7 @@ class EventInstructor(models.Model):
 
 class EventExtManager(models.Manager["EventExt"]):
     def get_queryset(self) -> models.QuerySet["EventExt"]:
-        return (
-            super()
-            .get_queryset()
-            .annotate(duration=Sum(F("meeting_times__end") - F("meeting_times__start")))
-        )
-        # TODO: use simpler expression when GeneratedField fixed
-        # return super().get_queryset().annotate(duration=Sum("meeting_times__duration"))
+        return super().get_queryset().annotate(duration=Sum("meeting_times__duration"))
 
 
 class EventExt(Event):
@@ -446,29 +440,18 @@ class EventExt(Event):
         verbose_name = "event"
 
 
-class EventMeetingTimeManager(models.Manager["EventMeetingTime"]):
-    def get_queryset(self) -> models.QuerySet["EventMeetingTime"]:
-        return super().get_queryset().annotate(duration=F("end") - F("start"))
-
-
 class EventMeetingTime(models.Model):
-    objects = EventMeetingTimeManager()
-
     event = models.ForeignKey(
         EventExt, on_delete=models.CASCADE, related_name="meeting_times"
     )
     start = models.DateTimeField()
     end = models.DateTimeField()
 
-    # TODO: Should use generated field instead of manager, but this is
-    # broken due to current Django bug, pending next release (> 5.0)
-    # ref: https://code.djangoproject.com/ticket/35019
-
-    # duration = models.GeneratedField(
-    #     expression=F("end") - F("start"),
-    #     output_field=models.DurationField(),
-    #     db_persist=False,
-    # )
+    duration = models.GeneratedField(
+        expression=F("end") - F("start"),
+        output_field=models.DurationField(),
+        db_persist=False,
+    )
 
     class Meta:
         constraints = [