diff --git a/sale_stock_picking_invoicing/wizards/stock_invoice_onshipping.py b/sale_stock_picking_invoicing/wizards/stock_invoice_onshipping.py
index f90a05d6eee..c519e3a9109 100644
--- a/sale_stock_picking_invoicing/wizards/stock_invoice_onshipping.py
+++ b/sale_stock_picking_invoicing/wizards/stock_invoice_onshipping.py
@@ -29,6 +29,39 @@ def _default_has_down_payment(self):
         "Has down payments", default=_default_has_down_payment, readonly=True
     )
 
+    def _get_fields_not_used_from_sale(self):
+        """Fields not used from Sale 'prepare' method"""
+        # For reference, fields get from 'prepare' method
+        #   "ref": self.client_order_ref or ''
+        #   "narration": self.note,
+        #   "campaign_id": self.campaign_id.id,
+        #   "medium_id": self.medium_id.id,
+        #   "source_id": self.source_id.id,
+        #   "team_id": self.team_id.id,
+        #   "partner_shipping_id": self.partner_shipping_id.id,
+        #   "partner_bank_id": self.company_id.partner_id.bank_ids.
+        #      filtered(lambda bank: bank.company_id.id in
+        #      (self.company_id.id, False))[:1].id,
+        #   "invoice_payment_term_id": self.payment_term_id.id,
+        #   "payment_reference": self.reference,
+        #   "transaction_ids": [(6, 0, self.transaction_ids.ids)],
+
+        return {
+            "move_type",
+            "currency_id",
+            "user_id",
+            "invoice_user_id",
+            "partner_id",
+            "fiscal_position_id",
+            "journal_id",  # company comes from the journal
+            "invoice_origin",
+            "invoice_line_ids",
+            "company_id",
+            # Another fields
+            "__last_update",
+            "display_name",
+        }
+
     def _build_invoice_values_from_pickings(self, pickings):
         invoice, values = super()._build_invoice_values_from_pickings(pickings)
 
@@ -65,40 +98,9 @@ def _build_invoice_values_from_pickings(self, pickings):
                 refs.add(sale_values["ref"])
                 narration.add(sale_values["narration"])
 
-                # Original dict from sale module, for reference:
-                # Fields to get:
-                #  "ref": self.client_order_ref or ''
-                #  "narration": self.note,
-                #  "campaign_id": self.campaign_id.id,
-                #  "medium_id": self.medium_id.id,
-                #  "source_id": self.source_id.id,
-                #  "team_id": self.team_id.id,
-                #  "partner_shipping_id": self.partner_shipping_id.id,
-                #  "partner_bank_id": self.company_id.partner_id.bank_ids.
-                #      filtered(lambda bank: bank.company_id.id in
-                #      (self.company_id.id, False))[:1].id,
-                #  "invoice_payment_term_id": self.payment_term_id.id,
-                #  "payment_reference": self.reference,
-                #  "transaction_ids": [(6, 0, self.transaction_ids.ids)],
-
-                # Fields to remove
-                vals_to_remove = {
-                    "move_type",
-                    "currency_id",
-                    "user_id",
-                    "invoice_user_id",
-                    "partner_id",
-                    "fiscal_position_id",
-                    "journal_id",  # company comes from the journal
-                    "invoice_origin",
-                    "invoice_line_ids",
-                    "company_id",
-                    # Another fields
-                    "__last_update",
-                    "display_name",
-                }
                 sale_values_rm = {
-                    k: sale_values[k] for k in set(sale_values) - vals_to_remove
+                    k: sale_values[k]
+                    for k in set(sale_values) - self._get_fields_not_used_from_sale()
                 }
 
                 values.update(sale_values_rm)
@@ -154,6 +156,28 @@ def _get_move_key(self, move):
 
         return key
 
+    def _get_fields_not_used_from_sale_line(self):
+        """Fields not used from Sale Line 'prepare' method"""
+        # For reference, fields get from original 'prepare' method
+        #   "sequence": self.sequence,
+        #   "discount": self.discount,
+
+        return {
+            "display_type",
+            "name",
+            "product_id",
+            "product_uom_id",
+            "quantity",
+            "price_unit",
+            "tax_ids",
+            "analytic_account_id",
+            "analytic_tag_ids",
+            "sale_line_ids",
+            # another fields
+            "__last_update",
+            "display_name",
+        }
+
     def _get_invoice_line_values(self, moves, invoice_values, invoice):
         values = super()._get_invoice_line_values(moves, invoice_values, invoice)
         move = fields.first(moves)
@@ -171,30 +195,11 @@ def _get_invoice_line_values(self, moves, invoice_values, invoice):
             if self._get_invoice_type() != "out_refund":
                 # Same make above, get fields informed in Sale Line dict
                 sale_line_values = move.sale_line_id._prepare_invoice_line()
-                # Original fields from sale module
-                # Fields do get
-                #     "sequence": self.sequence,
-                #     "discount": self.discount,
-
-                # Fields to remove
-                vals_to_remove = {
-                    "display_type",
-                    "name",
-                    "product_id",
-                    "product_uom_id",
-                    "quantity",
-                    "price_unit",
-                    "tax_ids",
-                    "analytic_account_id",
-                    "analytic_tag_ids",
-                    "sale_line_ids",
-                    # another fields
-                    "__last_update",
-                    "display_name",
-                }
+
                 sale_line_values_rm = {
                     k: sale_line_values[k]
-                    for k in set(sale_line_values) - vals_to_remove
+                    for k in set(sale_line_values)
+                    - self._get_fields_not_used_from_sale_line()
                 }
                 values.update(sale_line_values_rm)