Migrate stock value

Here's a patch containing some changes :
1) Currency used for migrating products is default currency of Commerce site.
2) Cost is transferred as well (if field_cost exists)
3) Stock value is migrated if stock module is enabled on commerce site
There's still a problem with this last one.
Value is taken from source site correctly.
Value is added to new entity but is converted to an array with a string and a language code and therefor not added to the integer field of stock ?
Anybody an idea why ?

I tested the above patch after installing migrate 7.x-2.x-dev and now everything works fine.
Can someone review the patch and commit it ?