diff --git a/InvenTree/order/models.py b/InvenTree/order/models.py
index 11d125b789..2e4ceb54e7 100644
--- a/InvenTree/order/models.py
+++ b/InvenTree/order/models.py
@@ -257,8 +257,9 @@ class PurchaseOrder(Order):
                 # update quantity and price
                 quantity_new = line.quantity + quantity
                 line.quantity = quantity_new
-                if line.purchase_price:
-                    line.purchase_price = supplier_part.get_price(quantity_new) / quantity_new
+                supplier_price = supplier_part.get_price(quantity_new)
+                if line.purchase_price and supplier_price:
+                    line.purchase_price = supplier_price / quantity_new
                 line.save()
 
                 return
diff --git a/InvenTree/order/views.py b/InvenTree/order/views.py
index fc7f376206..c62a3816d5 100644
--- a/InvenTree/order/views.py
+++ b/InvenTree/order/views.py
@@ -996,7 +996,14 @@ class OrderParts(AjaxView):
 
                 part.order_supplier = supplier_part.id if supplier_part else None
                 part.order_quantity = quantity
-                part.purchase_price = supplier_part.get_price(quantity) / quantity if supplier_part else None
+
+                # set supplier-price
+                if supplier_part:
+                    supplier_price = supplier_part.get_price(quantity)
+                    if supplier_price:
+                        part.purchase_price = supplier_price / quantity
+                if not hasattr(part, 'purchase_price'):
+                    part.purchase_price = None
 
                 self.parts.append(part)
 
@@ -1098,7 +1105,7 @@ class OrderParts(AjaxView):
                     continue
 
                 # get purchase price
-                purchase_price = item.purchase_price if item.purchase_price else None
+                purchase_price = item.purchase_price
 
                 order.add_line_item(supplier_part, quantity, purchase_price=purchase_price)