Set cost_price_method as Property as it depends of the company like the

cost_price

product.py

@@ -1,4 +1,5 @@
-#This file is part of Tryton.  The COPYRIGHT file at the top level of this repository contains the full copyright notices and license terms.
+#This file is part of Tryton.  The COPYRIGHT file at the top level of
+#this repository contains the full copyright notices and license terms.
 from trytond.osv import fields, OSV
 
 STATES = {
@@ -28,10 +29,10 @@ class Template(OSV):
             states=STATES, digits=(16, 4))
     cost_price_uom = fields.Function('get_price_uom', string='Cost Price',
             type="numeric", digits=(16, 4), states=STATES)
-    cost_price_method = fields.Selection([
+    cost_price_method = fields.Property(type='selection', selection=[
         ("fixed", "Fixed"),
         ("average", "Average")
-        ], "Cost Method", required=True, states=STATES)
+        ], string="Cost Method", required=True, states=STATES)
     default_uom = fields.Many2One('product.uom', 'Default UOM', required=True,
             states=STATES)
     active = fields.Boolean('Active')

product.xml

@@ -146,5 +146,12 @@
             <field name="perm_delete" eval="True"/>
         </record>
 
+        <record model="ir.property" id="property_product_cost_price_method">
+            <field name="name">cost_price_method</field>
+            <field name="field"
+                search="[('model.model', '=', 'product.template'), ('name', '=', 'cost_price_method')]"/>
+            <field name="value">,fixed</field>
+        </record>
+
     </data>
 </tryton>