diff --git a/openupgrade_scripts/scripts/sale_timesheet/14.0.1.0/post-migration.py b/openupgrade_scripts/scripts/sale_timesheet/14.0.1.0/post-migration.py
index 5d3572f4d2ab..23e2f7b389ae 100644
--- a/openupgrade_scripts/scripts/sale_timesheet/14.0.1.0/post-migration.py
+++ b/openupgrade_scripts/scripts/sale_timesheet/14.0.1.0/post-migration.py
@@ -22,7 +22,8 @@ def _fill_project_timesheet_product(env):
         env.cr,
         """UPDATE project_project pp
         SET timesheet_product_id = %s
-        WHERE pp.pricing_type IS NOT NULL AND pp.allow_timesheets""",
+        WHERE pp.pricing_type IS NOT NULL AND pp.allow_timesheets
+        AND timesheet_product_id IS NULL""",
         (product.id,),
     )
 
diff --git a/openupgrade_scripts/scripts/sale_timesheet/14.0.1.0/pre-migration.py b/openupgrade_scripts/scripts/sale_timesheet/14.0.1.0/pre-migration.py
index 35162e779e49..b216c5c81330 100644
--- a/openupgrade_scripts/scripts/sale_timesheet/14.0.1.0/pre-migration.py
+++ b/openupgrade_scripts/scripts/sale_timesheet/14.0.1.0/pre-migration.py
@@ -35,5 +35,6 @@ def migrate(env, version):
     openupgrade.rename_fields(env, _field_renames)
     map_pricing_type(env)
     openupgrade.logged_query(
-        env.cr, "ALTER TABLE project_project ADD timesheet_product_id int4"
+        env.cr,
+        "ALTER TABLE project_project ADD COLUMN IF NOT EXISTS timesheet_product_id int4",
     )