Length of og:description to be variable

Would it be possible to include an option in the settings for this plugin so that the number of characters copied into og:description can be changed?

At the moment og:description seems to be fixed at 160 characters as per the code below.

$wpfbogp_description = str_replace( “\r\n”, ‘ ‘ , substr( strip_tags( strip_shortcodes( $post->post_content ) ), 0, 160 ) );

http://wordpress.org/plugins/wp-facebook-open-graph-protocol/