diff --git a/fieldservice_account_analytic/models/fsm_order.py b/fieldservice_account_analytic/models/fsm_order.py
index daacfa0900..70ce44d587 100644
--- a/fieldservice_account_analytic/models/fsm_order.py
+++ b/fieldservice_account_analytic/models/fsm_order.py
@@ -56,8 +56,7 @@ def _onchange_customer_id_location(self):
             self.location_id = self.customer_id.service_location_id
 
     def write(self, vals):
-        res = super(FSMOrder, self).write(vals)
         for order in self:
-            if "customer_id" not in vals and order.customer_id is False:
-                order.customer_id = order.location_id.customer_id.id
-        return res
+            if "customer_id" not in vals and not order.customer_id:
+                vals.update({"customer_id": order.location_id.customer_id.id})
+        return super(FSMOrder, self).write(vals)
diff --git a/fieldservice_sale/models/fsm_order.py b/fieldservice_sale/models/fsm_order.py
index b9dbcaaf1c..2ef38b4413 100644
--- a/fieldservice_sale/models/fsm_order.py
+++ b/fieldservice_sale/models/fsm_order.py
@@ -20,3 +20,15 @@ def action_view_sales(self):
             "context": {"create": False},
             "name": _("Sales Orders"),
         }
+
+    def write(self, vals):
+        for order in self:
+            if "customer_id" not in vals and not order.customer_id:
+                vals.update({"customer_id": order.sale_id.partner_id.id})
+        return super(FSMOrder, self).write(vals)
+
+    def create(self, vals):
+        sale_id = self.env['sale.order'].browse(vals.get("sale_id"))
+        if sale_id:
+            vals["customer_id"] = sale_id.partner_id.id
+        return super(FSMOrder, self).create(vals)
diff --git a/fieldservice_stock_account/tests/test_fsm_stock_account.py b/fieldservice_stock_account/tests/test_fsm_stock_account.py
index bd3bf35ceb..f3c7205154 100644
--- a/fieldservice_stock_account/tests/test_fsm_stock_account.py
+++ b/fieldservice_stock_account/tests/test_fsm_stock_account.py
@@ -3,7 +3,6 @@
 
 import datetime
 
-from odoo.exceptions import UserError
 from odoo.tests.common import TransactionCase
 
 
@@ -77,7 +76,6 @@ def test_fsm_order(self):
         SR_2.action_confirm()
         fsm_order2.account_no_invoice()
         fsm_order2.bill_to = "contact"
-        with self.assertRaises(UserError):
-            fsm_order2.account_no_invoice()
+        fsm_order2.account_no_invoice()
         fsm_order2.customer_id = self.test_partner.id
         fsm_order2.account_no_invoice()