diff --git a/accounts/doctype/sales_invoice/sales_invoice.py b/accounts/doctype/sales_invoice/sales_invoice.py
index 956867d7abc..23114f0d78b 100644
--- a/accounts/doctype/sales_invoice/sales_invoice.py
+++ b/accounts/doctype/sales_invoice/sales_invoice.py
@@ -558,13 +558,14 @@ class DocType(SellingController):
 			
 	def validate_rate_with_refdoc(self):
 		"""Validate values with reference document with previous document"""
-		for d in self.doclist.get({"parentfield": "entries"}):
-			if d.so_detail:
-				self.check_value("Sales Order", d.sales_order, d.so_detail, 
-					d.export_rate, d.item_code)
-			if d.dn_detail:
-				self.check_value("Delivery Note", d.delivery_note, d.dn_detail, 
-					d.export_rate, d.item_code)
+		if cint(webnotes.defaults.get_global_default('maintain_same_sales_rate')):
+			for d in self.doclist.get({"parentfield": "entries"}):
+				if d.so_detail:
+					self.check_value("Sales Order", d.sales_order, d.so_detail, 
+						d.export_rate, d.item_code)
+				if d.dn_detail:
+					self.check_value("Delivery Note", d.delivery_note, d.dn_detail, 
+						d.export_rate, d.item_code)
 				
 	def check_value(self, ref_dt, ref_dn, ref_item_dn, val, item_code):
 		ref_val = webnotes.conn.get_value(ref_dt + " Item", ref_item_dn, "export_rate")
diff --git a/patches/july_2013/p01_same_sales_rate_patch.py b/patches/july_2013/p01_same_sales_rate_patch.py
new file mode 100644
index 00000000000..cc1f6daa998
--- /dev/null
+++ b/patches/july_2013/p01_same_sales_rate_patch.py
@@ -0,0 +1,9 @@
+def execute():
+	import webnotes
+	webnotes.reload_doc("setup", "doctype", "global_defaults")
+	
+	from webnotes.model.code import get_obj
+	gd = get_obj('Global Defaults')
+	gd.doc.maintain_same_sales_rate = 1
+	gd.doc.save()
+	gd.on_update()
\ No newline at end of file
diff --git a/patches/patch_list.py b/patches/patch_list.py
index 812f641fcb2..d15602d7993 100644
--- a/patches/patch_list.py
+++ b/patches/patch_list.py
@@ -246,4 +246,5 @@ patch_list = [
 	"execute:webnotes.reload_doc('accounts', 'DocType Mapper', 'Purchase Order-Purchase Invoice') # 2013-07-04 3:00",
 	"execute:webnotes.reload_doc('accounts', 'DocType Mapper', 'Purchase Receipt-Purchase Invoice') # 2013-07-04 3:00",
 	"execute:webnotes.delete_doc('Report', 'Sales Orders Pending To Be Delivered')",
+	"patches.july_2013.p01_same_sales_rate_patch",
 ]
diff --git a/setup/doctype/global_defaults/global_defaults.py b/setup/doctype/global_defaults/global_defaults.py
index dc7f6b4b735..a921229a160 100644
--- a/setup/doctype/global_defaults/global_defaults.py
+++ b/setup/doctype/global_defaults/global_defaults.py
@@ -48,6 +48,7 @@ keydict = {
 	'disable_rounded_total': 'disable_rounded_total',
 	"update_stock": "update_stock",
 	"auto_inventory_accounting": "auto_inventory_accounting",
+	'maintain_same_sales_rate' : 'maintain_same_sales_rate',
 }
 
 class DocType:
diff --git a/setup/doctype/global_defaults/global_defaults.txt b/setup/doctype/global_defaults/global_defaults.txt
index 175ca9414b6..1e1505a6b16 100644
--- a/setup/doctype/global_defaults/global_defaults.txt
+++ b/setup/doctype/global_defaults/global_defaults.txt
@@ -1,8 +1,8 @@
 [
  {
-  "creation": "2013-05-02 17:53:24", 
+  "creation": "2013-07-16 18:18:01", 
   "docstatus": 0, 
-  "modified": "2013-05-22 15:57:26", 
+  "modified": "2013-07-16 18:23:52", 
   "modified_by": "Administrator", 
   "owner": "Administrator"
  }, 
@@ -27,8 +27,6 @@
   "permlevel": 0
  }, 
  {
-  "amend": 0, 
-  "cancel": 0, 
   "create": 1, 
   "doctype": "DocPerm", 
   "name": "__common__", 
@@ -439,6 +437,12 @@
   "label": "Disable Rounded Total", 
   "read_only": 0
  }, 
+ {
+  "doctype": "DocField", 
+  "fieldname": "maintain_same_sales_rate", 
+  "fieldtype": "Check", 
+  "label": "Maintain same rate throughout sales cycle"
+ }, 
  {
   "doctype": "DocField", 
   "fieldname": "buying", 
@@ -526,6 +530,11 @@
   "label": "SMS Sender Name", 
   "read_only": 0
  }, 
+ {
+  "amend": 0, 
+  "cancel": 0, 
+  "doctype": "DocPerm"
+ }, 
  {
   "doctype": "DocPerm"
  }