diff --git a/erpnext/buying/doctype/purchase_order/purchase_order.py b/erpnext/buying/doctype/purchase_order/purchase_order.py
index d32e98e..29a8d59 100644
--- a/erpnext/buying/doctype/purchase_order/purchase_order.py
+++ b/erpnext/buying/doctype/purchase_order/purchase_order.py
@@ -252,6 +252,7 @@
 		self.update_prevdoc_status()
 
 		# Must be called after updating ordered qty in Material Request
+		# bin uses Material Request Items to recalculate & update
 		self.update_requested_qty()
 		self.update_ordered_qty()
 
diff --git a/erpnext/buying/doctype/purchase_order/test_purchase_order.py b/erpnext/buying/doctype/purchase_order/test_purchase_order.py
index 02d4865..1b231b3 100644
--- a/erpnext/buying/doctype/purchase_order/test_purchase_order.py
+++ b/erpnext/buying/doctype/purchase_order/test_purchase_order.py
@@ -90,6 +90,50 @@
 		frappe.db.set_value('Item', '_Test Item', 'over_billing_allowance', 0)
 		frappe.db.set_value("Accounts Settings", None, "over_billing_allowance", 0)
 
+	def test_update_remove_child_linked_to_mr(self):
+		"""Test impact on linked PO and MR on deleting/updating row."""
+		mr = make_material_request(qty=10)
+		po = make_purchase_order(mr.name)
+		po.supplier = "_Test Supplier"
+		po.save()
+		po.submit()
+
+		first_item_of_po = po.get("items")[0]
+		existing_ordered_qty = get_ordered_qty() # 10
+		existing_requested_qty = get_requested_qty() # 0
+
+		# decrease ordered qty by 3 (10 -> 7) and add item
+		trans_item = json.dumps([
+			{
+				'item_code': first_item_of_po.item_code,
+				'rate': first_item_of_po.rate,
+				'qty': 7,
+				'docname': first_item_of_po.name
+			},
+			{'item_code' : '_Test Item 2', 'rate' : 200, 'qty' : 2}
+		])
+		update_child_qty_rate('Purchase Order', trans_item, po.name)
+		mr.reload()
+
+		# requested qty increases as ordered qty decreases
+		self.assertEqual(get_requested_qty(), existing_requested_qty + 3) # 3
+		self.assertEqual(mr.items[0].ordered_qty, 7)
+
+		self.assertEqual(get_ordered_qty(), existing_ordered_qty - 3) # 7
+
+		# delete first item linked to Material Request
+		trans_item = json.dumps([
+			{'item_code' : '_Test Item 2', 'rate' : 200, 'qty' : 2}
+		])
+		update_child_qty_rate('Purchase Order', trans_item, po.name)
+		mr.reload()
+
+		# requested qty increases as ordered qty is 0 (deleted row)
+		self.assertEqual(get_requested_qty(), existing_requested_qty + 10) # 10
+		self.assertEqual(mr.items[0].ordered_qty, 0)
+
+		# ordered qty decreases as ordered qty is 0 (deleted row)
+		self.assertEqual(get_ordered_qty(), existing_ordered_qty - 10) # 0
 
 	def test_update_child(self):
 		mr = make_material_request(qty=10)
@@ -120,7 +164,6 @@
 		self.assertEqual(po.get("items")[0].amount, 1400)
 		self.assertEqual(get_ordered_qty(), existing_ordered_qty + 3)
 
-
 	def test_update_child_adding_new_item(self):
 		po = create_purchase_order(do_not_save=1)
 		po.items[0].qty = 4
@@ -129,6 +172,7 @@
 		pr = make_pr_against_po(po.name, 2)
 
 		po.load_from_db()
+		existing_ordered_qty = get_ordered_qty()
 		first_item_of_po = po.get("items")[0]
 
 		trans_item = json.dumps([
@@ -145,7 +189,8 @@
 		po.reload()
 		self.assertEquals(len(po.get('items')), 2)
 		self.assertEqual(po.status, 'To Receive and Bill')
-
+		# ordered qty should increase on row addition
+		self.assertEqual(get_ordered_qty(), existing_ordered_qty + 7)
 
 	def test_update_child_removing_item(self):
 		po = create_purchase_order(do_not_save=1)
@@ -156,6 +201,7 @@
 
 		po.reload()
 		first_item_of_po = po.get("items")[0]
+		existing_ordered_qty = get_ordered_qty()
 		# add an item
 		trans_item = json.dumps([
 			{
@@ -168,6 +214,10 @@
 		update_child_qty_rate('Purchase Order', trans_item, po.name)
 
 		po.reload()
+
+		# ordered qty should increase on row addition
+		self.assertEqual(get_ordered_qty(), existing_ordered_qty + 7)
+
 		# check if can remove received item
 		trans_item = json.dumps([{'item_code' : '_Test Item', 'rate' : 200, 'qty' : 7, 'docname': po.get("items")[1].name}])
 		self.assertRaises(frappe.ValidationError, update_child_qty_rate, 'Purchase Order', trans_item, po.name)
@@ -187,6 +237,9 @@
 		self.assertEquals(len(po.get('items')), 1)
 		self.assertEqual(po.status, 'To Receive and Bill')
 
+		# ordered qty should decrease (back to initial) on row deletion
+		self.assertEqual(get_ordered_qty(), existing_ordered_qty)
+
 	def test_update_child_perm(self):
 		po = create_purchase_order(item_code= "_Test Item", qty=4)
 
@@ -230,11 +283,13 @@
 
 		new_item_with_tax = frappe.get_doc("Item", "Test Item with Tax")
 
-		new_item_with_tax.append("taxes", {
-			"item_tax_template": "Test Update Items Template - _TC",
-			"valid_from": nowdate()
-		})
-		new_item_with_tax.save()
+		if not frappe.db.exists("Item Tax",
+			{"item_tax_template": "Test Update Items Template - _TC", "parent": "Test Item with Tax"}):
+			new_item_with_tax.append("taxes", {
+				"item_tax_template": "Test Update Items Template - _TC",
+				"valid_from": nowdate()
+			})
+			new_item_with_tax.save()
 
 		tax_template = "_Test Account Excise Duty @ 10 - _TC"
 		item =  "_Test Item Home Desktop 100"
diff --git a/erpnext/controllers/accounts_controller.py b/erpnext/controllers/accounts_controller.py
index 8d53914..a73de44 100644
--- a/erpnext/controllers/accounts_controller.py
+++ b/erpnext/controllers/accounts_controller.py
@@ -1316,26 +1316,63 @@
 	p_doc = frappe.get_doc(parent_doctype, parent_doctype_name)
 	child_item = frappe.new_doc(child_doctype, p_doc, child_docname)
 	item = frappe.get_doc("Item", trans_item.get('item_code'))
+
 	for field in ("item_code", "item_name", "description", "item_group"):
-	    child_item.update({field: item.get(field)})
+		child_item.update({field: item.get(field)})
+
 	date_fieldname = "delivery_date" if child_doctype == "Sales Order Item" else "schedule_date"
 	child_item.update({date_fieldname: trans_item.get(date_fieldname) or p_doc.get(date_fieldname)})
+	child_item.stock_uom = item.stock_uom
 	child_item.uom = trans_item.get("uom") or item.stock_uom
 	child_item.warehouse = get_item_warehouse(item, p_doc, overwrite_warehouse=True)
 	conversion_factor = flt(get_conversion_factor(item.item_code, child_item.uom).get("conversion_factor"))
 	child_item.conversion_factor = flt(trans_item.get('conversion_factor')) or conversion_factor
+
 	if child_doctype == "Purchase Order Item":
-		child_item.base_rate = 1 # Initiallize value will update in parent validation
-		child_item.base_amount = 1 # Initiallize value will update in parent validation
+		# Initialized value will update in parent validation
+		child_item.base_rate = 1
+		child_item.base_amount = 1
 	if child_doctype == "Sales Order Item":
 		child_item.warehouse = get_item_warehouse(item, p_doc, overwrite_warehouse=True)
 		if not child_item.warehouse:
 			frappe.throw(_("Cannot find {} for item {}. Please set the same in Item Master or Stock Settings.")
 				.format(frappe.bold("default warehouse"), frappe.bold(item.item_code)))
+
 	set_child_tax_template_and_map(item, child_item, p_doc)
 	add_taxes_from_tax_template(child_item, p_doc)
 	return child_item
 
+def validate_child_on_delete(row, parent):
+	"""Check if partially transacted item (row) is being deleted."""
+	if parent.doctype == "Sales Order":
+		if flt(row.delivered_qty):
+			frappe.throw(_("Row #{0}: Cannot delete item {1} which has already been delivered").format(row.idx, row.item_code))
+		if flt(row.work_order_qty):
+			frappe.throw(_("Row #{0}: Cannot delete item {1} which has work order assigned to it.").format(row.idx, row.item_code))
+		if flt(row.ordered_qty):
+			frappe.throw(_("Row #{0}: Cannot delete item {1} which is assigned to customer's purchase order.").format(row.idx, row.item_code))
+
+	if parent.doctype == "Purchase Order" and flt(row.received_qty):
+		frappe.throw(_("Row #{0}: Cannot delete item {1} which has already been received").format(row.idx, row.item_code))
+
+	if flt(row.billed_amt):
+		frappe.throw(_("Row #{0}: Cannot delete item {1} which has already been billed.").format(row.idx, row.item_code))
+
+def update_bin_on_delete(row, doctype):
+	"""Update bin for deleted item (row)."""
+	from erpnext.stock.stock_balance import update_bin_qty, get_reserved_qty, get_ordered_qty, get_indented_qty
+	qty_dict = {}
+
+	if doctype == "Sales Order":
+		qty_dict["reserved_qty"] = get_reserved_qty(row.item_code, row.warehouse)
+	else:
+		if row.material_request_item:
+			qty_dict["indented_qty"] = get_indented_qty(row.item_code, row.warehouse)
+
+		qty_dict["ordered_qty"] = get_ordered_qty(row.item_code, row.warehouse)
+
+	update_bin_qty(row.item_code, row.warehouse, qty_dict)
+
 def validate_and_delete_children(parent, data):
 	deleted_children = []
 	updated_item_names = [d.get("docname") for d in data]
@@ -1344,33 +1381,16 @@
 			deleted_children.append(item)
 
 	for d in deleted_children:
-		if parent.doctype == "Sales Order":
-			if flt(d.delivered_qty):
-				frappe.throw(_("Row #{0}: Cannot delete item {1} which has already been delivered").format(d.idx, d.item_code))
-			if flt(d.work_order_qty):
-				frappe.throw(_("Row #{0}: Cannot delete item {1} which has work order assigned to it.").format(d.idx, d.item_code))
-			if flt(d.ordered_qty):
-				frappe.throw(_("Row #{0}: Cannot delete item {1} which is assigned to customer's purchase order.").format(d.idx, d.item_code))
-
-		if parent.doctype == "Purchase Order" and flt(d.received_qty):
-			frappe.throw(_("Row #{0}: Cannot delete item {1} which has already been received").format(d.idx, d.item_code))
-
-		if flt(d.billed_amt):
-			frappe.throw(_("Row #{0}: Cannot delete item {1} which has already been billed.").format(d.idx, d.item_code))
-
+		validate_child_on_delete(d, parent)
 		d.cancel()
 		d.delete()
-		
-		from erpnext.stock.stock_balance import update_bin_qty, get_reserved_qty, get_ordered_qty
-		# updating both will be time consuming, update it based on the doctype. reserved qty if sales order, otherwise ordered qty
-		if parent.doctype == "Sales Order":
-			update_bin_qty(d.item_code, d.warehouse, {
-				"reserved_qty": get_reserved_qty(d.item_code, d.warehouse)
-			}) 
-		else:
-			update_bin_qty(d.item_code, d.warehouse, {
-				"ordered_qty": get_ordered_qty(d.item_code, d.warehouse)
-			}) 
+
+	# need to update ordered qty in Material Request first
+	# bin uses Material Request Items to recalculate & update
+	parent.update_prevdoc_status()
+
+	for d in deleted_children:
+		update_bin_on_delete(d, parent.doctype)
 
 @frappe.whitelist()
 def update_child_qty_rate(parent_doctype, trans_items, parent_doctype_name, child_docname="items"):
diff --git a/erpnext/selling/doctype/sales_order/sales_order.py b/erpnext/selling/doctype/sales_order/sales_order.py
index e561291..fd9ddd8 100755
--- a/erpnext/selling/doctype/sales_order/sales_order.py
+++ b/erpnext/selling/doctype/sales_order/sales_order.py
@@ -150,7 +150,7 @@
 		if enq:
 			frappe.db.sql("update `tabOpportunity` set status = %s where name=%s",(flag,enq[0][0]))
 
-	def update_prevdoc_status(self, flag):
+	def update_prevdoc_status(self, flag=None):
 		for quotation in list(set([d.prevdoc_docname for d in self.get("items")])):
 			if quotation:
 				doc = frappe.get_doc("Quotation", quotation)
diff --git a/erpnext/selling/doctype/sales_order/test_sales_order.py b/erpnext/selling/doctype/sales_order/test_sales_order.py
index ee16f44..7752b7b 100644
--- a/erpnext/selling/doctype/sales_order/test_sales_order.py
+++ b/erpnext/selling/doctype/sales_order/test_sales_order.py
@@ -340,6 +340,9 @@
 		prev_total = so.get("base_total")
 		prev_total_in_words = so.get("base_in_words")
 
+		# get reserved qty before update items
+		reserved_qty_for_second_item = get_reserved_qty("_Test Item 2")
+
 		first_item_of_so = so.get("items")[0]
 		trans_item = json.dumps([
 			{'item_code' : first_item_of_so.item_code, 'rate' : first_item_of_so.rate, \
@@ -353,6 +356,10 @@
 		self.assertEqual(so.get("items")[-1].rate, 200)
 		self.assertEqual(so.get("items")[-1].qty, 7)
 		self.assertEqual(so.get("items")[-1].amount, 1400)
+
+		# reserved qty should increase after adding row
+		self.assertEqual(get_reserved_qty('_Test Item 2'), reserved_qty_for_second_item + 7)
+
 		self.assertEqual(so.status, 'To Deliver and Bill')
 
 		updated_total = so.get("base_total")
@@ -372,6 +379,9 @@
 		create_dn_against_so(so.name, 2)
 		make_sales_invoice(so.name)
 
+		# get reserved qty before update items
+		reserved_qty_for_second_item = get_reserved_qty("_Test Item 2")
+
 		# add an item so as to try removing items
 		trans_item = json.dumps([
 			{"item_code": '_Test Item', "qty": 5, "rate":1000, "docname": so.get("items")[0].name},
@@ -381,6 +391,9 @@
 		so.reload()
 		self.assertEqual(len(so.get("items")), 2)
 
+		# reserved qty should increase after adding row
+		self.assertEqual(get_reserved_qty('_Test Item 2'), reserved_qty_for_second_item + 2)
+
 		# check if delivered items can be removed
 		trans_item = json.dumps([{
 			"item_code": '_Test Item 2',
@@ -401,6 +414,10 @@
 
 		so.reload()
 		self.assertEqual(len(so.get("items")), 1)
+
+		# reserved qty should decrease (back to initial) after deleting row
+		self.assertEqual(get_reserved_qty('_Test Item 2'), reserved_qty_for_second_item)
+
 		self.assertEqual(so.status, 'To Deliver and Bill')
 
 
@@ -508,12 +525,18 @@
 
 		so = make_sales_order(item_code = "_Test Item", warehouse=None)
 
+		# get reserved qty of packed item
+		existing_reserved_qty = get_reserved_qty("_Packed Item")
+
 		added_item = json.dumps([{"item_code" : "_Product Bundle Item", "rate" : 200, 'qty' : 2}])
 		update_child_qty_rate('Sales Order', added_item, so.name)
 
 		so.reload()
 		self.assertEqual(so.packed_items[0].qty, 4)
 
+		# reserved qty in packed item should increase after adding bundle item
+		self.assertEqual(get_reserved_qty("_Packed Item"), existing_reserved_qty + 4)
+
 		# test uom and conversion factor change
 		update_uom_conv_factor = json.dumps([{
 			'item_code': so.get("items")[0].item_code,
@@ -528,6 +551,9 @@
 		so.reload()
 		self.assertEqual(so.packed_items[0].qty, 8)
 
+		# reserved qty in packed item should increase after changing bundle item uom
+		self.assertEqual(get_reserved_qty("_Packed Item"), existing_reserved_qty + 8)
+
 	def test_update_child_with_tax_template(self):
 		"""
 			Test Action: Create a SO with one item having its tax account head already in the SO.
diff --git a/erpnext/stock/doctype/bin/bin.json b/erpnext/stock/doctype/bin/bin.json
index 04d624e..8e79f0e 100644
--- a/erpnext/stock/doctype/bin/bin.json
+++ b/erpnext/stock/doctype/bin/bin.json
@@ -1,4 +1,5 @@
 {
+ "actions": [],
  "autoname": "MAT-BIN-.YYYY.-.#####",
  "creation": "2013-01-10 16:34:25",
  "doctype": "DocType",
@@ -112,7 +113,8 @@
   {
    "fieldname": "reserved_qty_for_sub_contract",
    "fieldtype": "Float",
-   "label": "Reserved Qty for sub contract"
+   "label": "Reserved Qty for sub contract",
+   "read_only": 1
   },
   {
    "fieldname": "ma_rate",
@@ -166,7 +168,8 @@
  "hide_toolbar": 1,
  "idx": 1,
  "in_create": 1,
- "modified": "2019-11-18 18:34:59.456882",
+ "links": [],
+ "modified": "2021-03-30 23:09:39.572776",
  "modified_by": "Administrator",
  "module": "Stock",
  "name": "Bin",
@@ -196,5 +199,6 @@
  ],
  "quick_entry": 1,
  "search_fields": "item_code,warehouse",
+ "sort_field": "modified",
  "sort_order": "ASC"
 }
\ No newline at end of file