diff --git a/yuthon_property_approval/models/property_lease_contract.py b/yuthon_property_approval/models/property_lease_contract.py
index e42e2721f..f63b6ce0a 100644
--- a/yuthon_property_approval/models/property_lease_contract.py
+++ b/yuthon_property_approval/models/property_lease_contract.py
@@ -150,7 +150,7 @@ class PropertyLeaseContract(models.Model):
     def _onchange_unit_price(self):
         for i in self:
             if i.total_area and i.rent:
-                i.unit_price = i.total_area / i.rent
+                i.unit_price = i.rent / i.total_area
 
     @api.depends('breakdown_ids')
     def _compute_total_contract_receivables(self):
@@ -369,8 +369,7 @@ class PropertyLeaseContract(models.Model):
                 all_period_rent = record.do_generate_details_core(start_date, first_year_end_date, False)
                 record.first_year_rent = all_period_rent
 
-
-    def do_generate_details_core(self, start_date, end_date, write_db=False):
+    def do_generate_details_core(self, start_date=None, end_date=None, write_db=False):
         all_period_rent = 0
 
         monthly_amount = self.total_area * self.unit_price