Significant memory usage for large number of field collections with node reference to book pages.

Memory usage becomes huge when we use book node reference in an node add / edit page and add large number of book references (say 60) using add another feature of field collection.
We can optimize the memory usage in that case by not using book_get_books() which uses a static caching and load large number of fields. All of these fields are not necessary when called from function _book_add_form_elements().