diff --git a/addons/purchase/models/purchase.py b/addons/purchase/models/purchase.py
index f5e3a406b40..b5e95d28efc 100644
--- a/addons/purchase/models/purchase.py
+++ b/addons/purchase/models/purchase.py
@@ -863,12 +863,18 @@ class ProcurementOrder(models.Model):
         schedule_date = (procurement_date_planned - relativedelta(days=self.company_id.po_lead))
         return schedule_date
 
-    def _get_purchase_order_date(self, schedule_date):
+    def _get_purchase_order_date(self, partner, schedule_date):
         """Return the datetime value to use as Order Date (``date_order``) for the
            Purchase Order created to satisfy the given procurement. """
         self.ensure_one()
-        seller_delay = int(self.product_id._select_seller(quantity=self.product_qty, uom_id=self.product_uom).delay)
-        return schedule_date - relativedelta(days=seller_delay)
+
+        seller = self.product_id._select_seller(
+            partner_id=partner,
+            quantity=self.product_qty,
+            date=fields.Date.to_string(schedule_date),
+            uom_id=self.product_uom)
+
+        return schedule_date - relativedelta(days=int(seller.delay))
 
     @api.multi
     def _prepare_purchase_order_line(self, po, supplier):
@@ -917,7 +923,7 @@ class ProcurementOrder(models.Model):
     def _prepare_purchase_order(self, partner):
         self.ensure_one()
         schedule_date = self._get_purchase_schedule_date()
-        purchase_date = self._get_purchase_order_date(schedule_date)
+        purchase_date = self._get_purchase_order_date(partner, schedule_date)
         fpos = self.env['account.fiscal.position'].with_context(company_id=self.company_id.id).get_fiscal_position(partner.id)
 
         gpo = self.rule_id.group_propagation_option
diff --git a/addons/stock/models/stock_warehouse.py b/addons/stock/models/stock_warehouse.py
index e7cfb8ccf4a..0025c742d91 100644
--- a/addons/stock/models/stock_warehouse.py
+++ b/addons/stock/models/stock_warehouse.py
@@ -799,11 +799,14 @@ class Orderpoint(models.Model):
                 res[orderpoint_id] -= move_qty
         return res
 
-    def _get_date_planned(self, start_date):
+    def _get_date_planned(self, product_qty, start_date):
         days = self.lead_days or 0.0
         if self.lead_type == 'supplier':
             # These days will be substracted when creating the PO
-            days += self.product_id._select_seller().delay or 0.0
+            days += self.product_id._select_seller(
+                quantity=product_qty,
+                date=fields.Date.to_string(start_date),
+                uom_id=self.product_uom).delay or 0.0
         date_planned = start_date + relativedelta.relativedelta(days=days)
         return date_planned.strftime(DEFAULT_SERVER_DATE_FORMAT)
 
@@ -811,7 +814,7 @@ class Orderpoint(models.Model):
     def _prepare_procurement_values(self, product_qty, date=False, group=False):
         return {
             'name': self.name,
-            'date_planned': date or self._get_date_planned(datetime.today()),
+            'date_planned': date or self._get_date_planned(product_qty, datetime.today()),
             'product_id': self.product_id.id,
             'product_qty': product_qty,
             'company_id': self.company_id.id,
diff --git a/addons/stock_calendar/models/procurement.py b/addons/stock_calendar/models/procurement.py
index 9fb0cc1dd01..b8cb26d64b2 100644
--- a/addons/stock_calendar/models/procurement.py
+++ b/addons/stock_calendar/models/procurement.py
@@ -28,10 +28,10 @@ class ProcurementOrder(models.Model):
                         'next_delivery_date': delivery_date.strftime(DEFAULT_SERVER_DATETIME_FORMAT),
                         'next_purchase_date': purchase_date.strftime(DEFAULT_SERVER_DATETIME_FORMAT)})
 
-    def _get_purchase_order_date(self, schedule_date):
+    def _get_purchase_order_date(self, partner, schedule_date):
         if self.next_purchase_date:
             return fields.Datetime.from_string(self.next_purchase_date)
-        return super(ProcurementOrder, self)._get_purchase_order_date(schedule_date)
+        return super(ProcurementOrder, self)._get_purchase_order_date(partner, schedule_date)
 
     def _get_purchase_schedule_date(self):
         if self.next_delivery_date: