Authorize.net AIM Additional Charge

/**
 Additional charge using Authorize.net AIM gateway
 */
function my_em_add_Authorize_surcharge($sale, $EM_Booking, $EM_Gateway_Authorize_AIM){

	$count = $EM_Booking->get_tickets_bookings()->tickets_bookings;
	$price = 0;
	foreach( $EM_Booking->get_tickets_bookings()->tickets_bookings as $EM_Ticket_Booking ){
		$price += round($EM_Ticket_Booking->get_price() / $EM_Ticket_Booking->get_spaces(), 2);
	}
	$price = ($price  * .02);
	$sale->addLineItem( 0, 'Charge', 'Booking Charge', 1, $price, 'Y' );

	return $sale;
}
add_filter('em_gateawy_authorize_aim_sale_var','my_em_add_Authorize_surcharge',1,3);