diff --git a/src/dispatch/cost_model/models.py b/src/dispatch/cost_model/models.py
index 69e15f7417f2..878aa0b9936b 100644
--- a/src/dispatch/cost_model/models.py
+++ b/src/dispatch/cost_model/models.py
@@ -43,7 +43,7 @@ class CostModelActivity(Base):
     id = Column(Integer, primary_key=True)
     plugin_event_id = Column(Integer, ForeignKey(PluginEvent.id, ondelete="CASCADE"))
     plugin_event = relationship(PluginEvent, backref="plugin_event")
-    response_time_seconds = Column(Integer, default=300)
+    response_time_seconds = Column(Integer, default=0)
     enabled = Column(Boolean, default=True)
 
 
@@ -69,7 +69,7 @@ class CostModelActivityBase(DispatchBase):
     """Base class for cost model activity resources"""
 
     plugin_event: PluginEventRead
-    response_time_seconds: int | None = 300
+    response_time_seconds: int | None = None
     enabled: bool | None = Field(True, nullable=True)
 
 
diff --git a/src/dispatch/cost_model/service.py b/src/dispatch/cost_model/service.py
index 50568f68b79e..7877511d7cf3 100644
--- a/src/dispatch/cost_model/service.py
+++ b/src/dispatch/cost_model/service.py
@@ -20,12 +20,12 @@
 def has_unique_plugin_event(cost_model_in: CostModelRead) -> bool:
     seen = set()
     for activity in cost_model_in.activities:
-        if activity.plugin_event.id in seen:
+        if activity.response_time_seconds in seen:
             log.warning(
-                f"Duplicate plugin event id detected. Please ensure all plugin events are unique for each cost model. Duplicate id: {activity.plugin_event.id}"
+                f"Duplicate response time detected. Please ensure all response times are unique for each cost model. Duplicate time: {activity.response_time_seconds}"
             )
             return False
-        seen.add(activity.plugin_event.id)
+        seen.add(activity.response_time_seconds)
     return True
 
 
@@ -34,16 +34,14 @@ def get_default(*, db_session, project_id: int) -> CostModel:
     return (
         db_session.query(CostModel)
         .filter(CostModel.project_id == project_id)
-        .order_by(CostModel.created_at.desc())
+        .order_by(CostModel.created_at.asc())
         .first()
     )
 
 
 def get_all(*, db_session, project_id: int) -> list[CostModel]:
     """Returns all cost models."""
-    if project_id:
-        return db_session.query(CostModel).filter(CostModel.project_id == project_id)
-    return db_session.query(CostModel)
+    return db_session.query(CostModel).all()
 
 
 def get_cost_model_activity_by_id(*, db_session, cost_model_activity_id: int) -> CostModelActivity:
@@ -70,7 +68,7 @@ def update_cost_model_activity(*, db_session, cost_model_activity_in: CostModelA
         db_session=db_session, cost_model_activity_id=cost_model_activity_in.id
     )
 
-    cost_model_activity.response_time_seconds = cost_model_activity_in.response_time_seconds
+    cost_model_activity.response_time_seconds = 0
     cost_model_activity.enabled = cost_model_activity_in.enabled
     cost_model_activity.plugin_event_id = cost_model_activity_in.plugin_event.id
 
@@ -104,12 +102,10 @@ def delete(*, db_session, cost_model_id: int):
     db_session.commit()
 
 
-def update(*, db_session, cost_model_in: CostModelUpdate) -> CostModel:
+def update(*, db_session, cost_model_in: CostModelUpdate, cost_model_id: int) -> CostModel:
     """Updates a cost model."""
-    if not has_unique_plugin_event(cost_model_in):
-        raise KeyError("Unable to update cost model. Duplicate plugin event ids detected.")
 
-    cost_model = get_cost_model_by_id(db_session=db_session, cost_model_id=cost_model_in.id)
+    cost_model = get_cost_model_by_id(db_session=db_session, cost_model_id=cost_model_id)
     if not cost_model:
         raise ValueError("Unable to update cost model. No cost model found with that id.")
 
@@ -121,6 +117,8 @@ def update(*, db_session, cost_model_in: CostModelUpdate) -> CostModel:
         cost_model_in.updated_at if cost_model_in.updated_at else datetime.utcnow()
     )
 
+    cost_model.updated_at = cost_model.created_at
+
     # Update all recognized activities. Delete all removed activities.
     update_activities = []
     delete_activities = []
@@ -132,7 +130,6 @@ def update(*, db_session, cost_model_in: CostModelUpdate) -> CostModel:
                 update_activities.append((activity, activity_in))
                 cost_model_in.activities.pop(idx_in)
                 updated = True
-                break
         if updated:
             continue
 
@@ -142,9 +139,6 @@ def update(*, db_session, cost_model_in: CostModelUpdate) -> CostModel:
     for activity, activity_in in update_activities:
         activity.response_time_seconds = activity_in.response_time_seconds
         activity.enabled = activity_in.enabled
-        activity.plugin_event = plugin_service.get_plugin_event_by_id(
-            db_session=db_session, plugin_event_id=activity_in.plugin_event.id
-        )
 
     for activity in delete_activities:
         cost_model_service.delete_cost_model_activity(
@@ -169,8 +163,6 @@ def update(*, db_session, cost_model_in: CostModelUpdate) -> CostModel:
 
 def create(*, db_session, cost_model_in: CostModelCreate) -> CostModel:
     """Creates a new cost model."""
-    if not has_unique_plugin_event(cost_model_in):
-        raise KeyError("Unable to update cost model. Duplicate plugin event ids detected.")
 
     project = project_service.get_by_name_or_raise(
         db_session=db_session, project_in=cost_model_in.project
diff --git a/src/dispatch/cost_model/views.py b/src/dispatch/cost_model/views.py
index 8d41b8e310a7..29984e339665 100644
--- a/src/dispatch/cost_model/views.py
+++ b/src/dispatch/cost_model/views.py
@@ -42,7 +42,7 @@ def create_cost_model(
 
 @router.put(
     "/{cost_model_id}",
-    summary="Modifies an existing cost model.",
+    summary="Creates a new cost model.",
     response_model=CostModelRead,
     dependencies=[Depends(PermissionsDependency([SensitiveProjectActionPermission]))],
 )