diff --git a/erpnext/controllers/stock_controller.py b/erpnext/controllers/stock_controller.py
index cb44b73..f92e884 100644
--- a/erpnext/controllers/stock_controller.py
+++ b/erpnext/controllers/stock_controller.py
@@ -405,7 +405,7 @@
 	def set_rate_of_stock_uom(self):
 		if self.doctype in ["Purchase Receipt", "Purchase Invoice", "Purchase Order", "Sales Invoice", "Sales Order", "Delivery Note", "Quotation"]:
 			for d in self.get("items"):
-				d.stock_uom_rate = d.rate / d.conversion_factor
+				d.stock_uom_rate = d.rate / (d.conversion_factor or 1)
 
 	def validate_internal_transfer(self):
 		if self.doctype in ('Sales Invoice', 'Delivery Note', 'Purchase Invoice', 'Purchase Receipt') \
diff --git a/erpnext/controllers/taxes_and_totals.py b/erpnext/controllers/taxes_and_totals.py
index 220c876..f976b17 100644
--- a/erpnext/controllers/taxes_and_totals.py
+++ b/erpnext/controllers/taxes_and_totals.py
@@ -111,10 +111,12 @@
 					item.rate_with_margin, item.base_rate_with_margin = self.calculate_margin(item)
 					if flt(item.rate_with_margin) > 0:
 						item.rate = flt(item.rate_with_margin * (1.0 - (item.discount_percentage / 100.0)), item.precision("rate"))
-						if not item.discount_amount:
+
+						if item.discount_amount and not item.discount_percentage:
+							item.rate = item.rate_with_margin - item.discount_amount
+						else:
 							item.discount_amount = item.rate_with_margin - item.rate
-						elif not item.discount_percentage:
-							item.rate -= item.discount_amount
+
 					elif flt(item.price_list_rate) > 0:
 						item.discount_amount = item.price_list_rate - item.rate
 				elif flt(item.price_list_rate) > 0 and not item.discount_amount: