Is it possible to get weight(order index) of multi field "field collection".This weight is needed inside computed field which is inside field collection.I tried the following but it returns empty

$wrapper = entity_metadata_wrapper('field_collection_item', $entity);    
$instance = field_read_instance('field_collection_item',$wrapper, 'bundle_name');
dpm($instance['widget']['weight']);

Here is the structure

main_content-contains field collection (multi value)
------field collection(s)-contains 1 text field and 1 computed field
------|----item 0
------|-------|-------computed_field <---here how to get weight of field collection item ie 0
------|----item 1
------|-------|-------computed_field <---here how to get weight of field collection item ie 1
------|----item 2
------|-------|-------computed_field
------|----item n
------|-------|-------computed_field