diff --git a/erpnext/assets/doctype/asset_maintenance/asset_maintenance.js b/erpnext/assets/doctype/asset_maintenance/asset_maintenance.js
index 1583daf..3c135d4 100644
--- a/erpnext/assets/doctype/asset_maintenance/asset_maintenance.js
+++ b/erpnext/assets/doctype/asset_maintenance/asset_maintenance.js
@@ -24,7 +24,28 @@
 				return indicator;
 			}
 		);
+
+		frm.set_query('select_serial_no', function(doc){
+			return {
+				asset: frm.doc.asset_name
+			}
+		})
 	},
+
+	select_serial_no: (frm) => {
+		let serial_nos = frm.doc.serial_no || frm.doc.select_serial_no;
+		if (serial_nos) {
+			serial_nos = serial_nos.split('\n');
+			serial_nos.push(frm.doc.select_serial_no);
+
+			const unique_sn = serial_nos.filter(function(elem, index, self) {
+			    return index === self.indexOf(elem);
+			});
+
+			frm.set_value("serial_no", unique_sn.join('\n'));
+		}
+	},
+
 	refresh: (frm) => {
 		if(!frm.is_new()) {
 			frm.trigger('make_dashboard');
diff --git a/erpnext/assets/doctype/asset_maintenance/asset_maintenance.json b/erpnext/assets/doctype/asset_maintenance/asset_maintenance.json
index f36fe4e..c254fe1 100644
--- a/erpnext/assets/doctype/asset_maintenance/asset_maintenance.json
+++ b/erpnext/assets/doctype/asset_maintenance/asset_maintenance.json
@@ -209,6 +209,38 @@
    "bold": 0, 
    "collapsible": 0, 
    "columns": 0, 
+   "fieldname": "select_serial_no", 
+   "fieldtype": "Link", 
+   "hidden": 0, 
+   "ignore_user_permissions": 0, 
+   "ignore_xss_filter": 0, 
+   "in_filter": 0, 
+   "in_global_search": 0, 
+   "in_list_view": 0, 
+   "in_standard_filter": 0, 
+   "label": "Select Serial No", 
+   "length": 0, 
+   "no_copy": 0, 
+   "options": "Serial No", 
+   "permlevel": 0, 
+   "precision": "", 
+   "print_hide": 0, 
+   "print_hide_if_no_value": 0, 
+   "read_only": 0, 
+   "remember_last_selected_value": 0, 
+   "report_hide": 0, 
+   "reqd": 0, 
+   "search_index": 0, 
+   "set_only_once": 0, 
+   "translatable": 0, 
+   "unique": 0
+  }, 
+  {
+   "allow_bulk_edit": 0, 
+   "allow_on_submit": 0, 
+   "bold": 0, 
+   "collapsible": 0, 
+   "columns": 0, 
    "fieldname": "serial_no", 
    "fieldtype": "Small Text", 
    "hidden": 0, 
@@ -221,12 +253,12 @@
    "label": "Serial No", 
    "length": 0, 
    "no_copy": 0, 
-   "options": "asset_name.serial_no", 
+   "options": "", 
    "permlevel": 0, 
    "precision": "", 
    "print_hide": 0, 
    "print_hide_if_no_value": 0, 
-   "read_only": 1, 
+   "read_only": 0, 
    "remember_last_selected_value": 0, 
    "report_hide": 0, 
    "reqd": 0, 
@@ -465,7 +497,7 @@
  "issingle": 0, 
  "istable": 0, 
  "max_attachments": 0, 
- "modified": "2018-04-20 08:39:27.072622", 
+ "modified": "2018-05-18 16:16:56.181695", 
  "modified_by": "Administrator", 
  "module": "Assets", 
  "name": "Asset Maintenance", 
diff --git a/erpnext/assets/doctype/asset_maintenance/asset_maintenance.py b/erpnext/assets/doctype/asset_maintenance/asset_maintenance.py
index b30685f..7551eae 100644
--- a/erpnext/assets/doctype/asset_maintenance/asset_maintenance.py
+++ b/erpnext/assets/doctype/asset_maintenance/asset_maintenance.py
@@ -11,9 +11,6 @@
 
 class AssetMaintenance(Document):
 	def validate(self):
-		if not self.serial_no:
-			self.serial_no = frappe.db.get_value("Asset", self.asset_name, 'serial_no')
-
 		for task in self.get('asset_maintenance_tasks'):
 			if task.end_date and (getdate(task.start_date) >= getdate(task.end_date)):
 				throw(_("Start date should be less than end date for task {0}").format(task.maintenance_task))
diff --git a/erpnext/stock/doctype/item/item.js b/erpnext/stock/doctype/item/item.js
index cdfbcae..6332d71 100644
--- a/erpnext/stock/doctype/item/item.js
+++ b/erpnext/stock/doctype/item/item.js
@@ -228,9 +228,13 @@
 			}
 		}
 
-		frm.fields_dict["item_defaults"].grid.get_field("buying_cost_center").get_query = function(doc) {
+		frm.fields_dict["item_defaults"].grid.get_field("buying_cost_center").get_query = function(doc, cdt, cdn) {
+			const row = locals[cdt][cdn];
 			return {
-				filters: { "is_group": 0 }
+				filters: { 
+					"is_group": 0,
+					"company": row.company
+				}
 			}
 		}
 
diff --git a/erpnext/stock/doctype/material_request/material_request.js b/erpnext/stock/doctype/material_request/material_request.js
index 8e66b55..62ea2b6 100644
--- a/erpnext/stock/doctype/material_request/material_request.js
+++ b/erpnext/stock/doctype/material_request/material_request.js
@@ -45,6 +45,8 @@
 					stock_qty: item.stock_qty,
 					company: frm.doc.company,
 					conversion_rate: 1,
+					name: frm.doc.name,
+					material_request_type: frm.doc.material_request_type,
 					plc_conversion_rate: 1,
 					rate: item.rate,
 					conversion_factor: item.conversion_factor
diff --git a/erpnext/stock/get_item_details.py b/erpnext/stock/get_item_details.py
index 562ac68..8a194fa 100644
--- a/erpnext/stock/get_item_details.py
+++ b/erpnext/stock/get_item_details.py
@@ -210,8 +210,8 @@
 	warehouse = user_default_warehouse or item_defaults.get("default_warehouse") or args.warehouse
 
 	material_request_type = ''
-	if args.get('doctype') == "Material Request":
-		material_request_type = frappe.db.get_value('Material Request',
+	if args.get('doctype') == "Material Request" and not args.get('material_request_type'):
+		args['material_request_type'] = frappe.db.get_value('Material Request',
 			args.get('name'), 'material_request_type')
 
 	#Set the UOM to the Default Sales UOM or Default Purchase UOM if configured in the Item Master
@@ -219,7 +219,7 @@
 		if args.get('doctype') in ['Quotation', 'Sales Order', 'Delivery Note', 'Sales Invoice']:
 			args.uom = item.sales_uom if item.sales_uom else item.stock_uom
 		elif (args.get('doctype') in ['Purchase Order', 'Purchase Receipt', 'Purchase Invoice']) or \
-			(args.get('doctype') == 'Material Request' and material_request_type == 'Purchase'):
+			(args.get('doctype') == 'Material Request' and args.get('material_request_type') == 'Purchase'):
 			args.uom = item.purchase_uom if item.purchase_uom else item.stock_uom
 		else:
 			args.uom = item.stock_uom