wp_ajax_ not calling to class object

I have ajax within a class, which has several instances of this same class.

Question is: shouldn’t the following line of code reference the $this of the correct object?
add_action( 'wp_ajax_my_ajax_save', array( &$this, 'ajax_save_callback' ) );

Instead it calls the ajax_save_callback() to only the first object. I know this because $this-> settings are only for the first object.

Thank you.