sort not working PIP

mods.php

<?php
add_action( 'wc_pip_styles','add_custom_css' );
function add_custom_css(){
	?>
	.customer-details {
        margin-left: -15px;
        margin-right: -15px;
    }
	.customer-details li {
        padding: 0 15px;
        width: 50%;
        -webkit-box-sizing: border-box;
        -moz-box-sizing: border-box;
        box-sizing: border-box;
    }
	.customer-email, .customer-phone {
		float:left;
		clear:both;
	}
	.customer-name_board_copy {
		float:right;
		margin-top:-15px;
	}
	.customer-name_board_font, .customer-batch {
		float:right;
		clear:right;
	}

	table thead.order-table-head th {
		border-color: #DDD;
	}
	ul.customer-details {
		list-style:none;
		height:60px;
	}
	table.packing-list-order-table .breadcrumbs {
		display:none;
	}
	<?php
}
add_filter( 'wc_pip_document_shipping_method', 'remove_price_from_shipping_method', 10, 3);
function remove_price_from_shipping_method( $shipping_method, $type, $order ){
	if ( 'packing-list' === $type) :
	if ( $get_shipping_method = $order->get_shipping_method() ) {

			$shipping_method = $get_shipping_method; //. '<br>' . wc_price( $this->order->get_total_shipping() );
		} else {
			$shipping_method =  __( 'No shipping', 'woocommerce-pip' );
		}
	endif;
		
	return $shipping_method;	
}
add_filter( 'wc_pip_document_table_headers', 'custom_table_headers', 10, 3);
function custom_table_headers($table_headers, $order_id, $type ){

	if ('packing-list' === $type ) :
		unset($table_headers['weight']);
		unset($table_headers['id']);
	endif;
	
	return $table_headers;
}
add_filter( 'wc_pip_document_table_footer', 'add_custom_rows_of_data_invoice',10,3);
function add_custom_rows_of_data_invoice( $rows, $type, $order_id ){
	if ('packing-list' === $type) :
		$rows = array();
	endif;
	if ('invoice' === $type) :
		$rows = $rows;
	endif;
	return $rows;
}
add_filter('wc_pip_document_table_row_cells','remove_price_from_cells',10,5);
function remove_price_from_cells( $table_row_cells, $type, $item_id, $item, $product ){
	
	 if ('packing-list' === $type ) :	
		unset($table_row_cells['weight']);
		unset($table_row_cells['id']);
		// if (  !empty( $item[ 'composite_parent' ] ) && !$product->is_type('simple')   ) :
		if ( empty($product->get_sku()) ) :  // no sku present
			unset($table_row_cells['quantity']);
			unset($table_row_cells['product']);
			unset($table_row_cells['sku']);

		endif;
		
	 endif;	
	 if ('invoice' === $type ) :	
		unset($table_row_cells['weight']);
		
		if ( !empty( $item[ 'composite_parent' ] ) && !$product->is_type('simple') )  :
			$table_row_cells['quantity'] = '';
			$table_row_cells['price'] = '';
			// $table_row_cells['product'] = print_r($item['composite_data']);
		endif;
		
	 endif;
 return $table_row_cells;
}
add_filter( 'wc_pip_document_customer_details', 'add_in_extra_order_details', 10, 3);
function add_in_extra_order_details($customer_details, $order_id, $type ){
	$order = wc_get_order($order_id);
	
	
	if ('packing-list' === $type ) :
		$customer_details = array();
		
		if ( isset( $order->billing_email ) && $order->billing_email ) {

			$customer_details['customer-email'] = array(
				'label' => __( 'Email:', 'woocommerce-pip' ),
				'value' => '<a class="packingphone" href="mailto:' . $order->billing_email . '">' . $order->billing_email . '</a>',
			);
		}

		if ( isset( $order->billing_phone ) && $order->billing_phone ) {

			$customer_details['customer-phone'] = array(
				'label' => __( 'Phone:', 'woocommerce-pip' ),
				'value' => '<a class="thisone" href="tel:' . $order->billing_phone . '">' . $order->billing_phone . '</a>',
			);
		}
		if ( get_post_meta($order_id, 'name_board_copy',true) != '' ) {
		$name_board_copy = get_post_meta($order_id, 'name_board_copy', true);
		$customer_details['customer-name_board_copy'] = array(
				'label' => __( 'Name Board Copy:', 'woocommerce-pip' ),
				'value' => $name_board_copy,
			);
		}
		if ( get_post_meta($order_id, 'name_board_font',true) != '' ) {
		$name_board_font = get_post_meta($order_id, 'name_board_font', true);
		$customer_details['customer-name_board_font'] = array(
				'label' => __( 'Name Board Font:', 'woocommerce-pip' ),
				'value' => $name_board_font,
			);
		}
		if ( get_post_meta($order_id, 'batch',true) != '' ) {
		$batch = get_post_meta($order_id, 'batch', true);
		$customer_details['customer-batch'] = array(
				'label' => __( 'Batch:', 'woocommerce-pip' ),
				'value' => $batch,
			);
		}
		if ( get_post_meta($order_id, 'bin',true) != '' ) {
		$bin = get_post_meta($order_id, 'bin', true);
		$customer_details['customer-bin'] = array(
				'label' => __( 'Bin:', 'woocommerce-pip' ),
				'value' => $bin,
			);
		}		
	endif;
	
	if ('invoice' === $type ) :
		$customer_details = array();
		
		if ( isset( $order->billing_email ) && $order->billing_email ) {

			$customer_details['customer-email'] = array(
				'label' => __( 'Email:', 'woocommerce-pip' ),
				'value' => '<a class="packingphone" href="mailto:' . $order->billing_email . '">' . $order->billing_email . '</a>',
			);
		}

		if ( isset( $order->billing_phone ) && $order->billing_phone ) {

			$customer_details['customer-phone'] = array(
				'label' => __( 'Phone:', 'woocommerce-pip' ),
				'value' => '<a class="thisone" href="tel:' . $order->billing_phone . '">' . $order->billing_phone . '</a>',
			);
		}
		if ( get_post_meta($order_id, 'name_board_copy',true) != '' ) {
		$name_board_copy = get_post_meta($order_id, 'name_board_copy', true);
		$customer_details['customer-name_board_copy'] = array(
				'label' => __( 'Name Board Copy:', 'woocommerce-pip' ),
				'value' => $name_board_copy,
			);
		}
		if ( get_post_meta($order_id, 'name_board_font',true) != '' ) {
		$name_board_font = get_post_meta($order_id, 'name_board_font', true);
		$customer_details['customer-name_board_font'] = array(
				'label' => __( 'Name Board Font:', 'woocommerce-pip' ),
				'value' => $name_board_font,
			);
		}
		if ( get_post_meta($order_id, 'batch',true) != '' ) {
		$batch = get_post_meta($order_id, 'batch', true);
		$customer_details['customer-batch'] = array(
				'label' => __( 'Batch:', 'woocommerce-pip' ),
				'value' => $batch,
			);
		}
		if ( get_post_meta($order_id, 'bin',true) != '' ) {
		$bin = get_post_meta($order_id, 'bin', true);
		$customer_details['customer-bin'] = array(
				'label' => __( 'Bin:', 'woocommerce-pip' ),
				'value' => $bin,
			);
		}
	endif;	
	
	return $customer_details;
}
add_action( 'wc_pip_header', 'render_custom_headers',1,4); 
function render_custom_headers( $type, $action, $document, $order ){
 
	if ('packing-list' === $type ) :
	
		$view_order_url = is_admin() && 'send_email' !== $action ? admin_url( 'post.php?post=' . $order->id . '&action=edit' ) : wc_get_endpoint_url( 'view-order', $order->id, get_permalink( wc_get_page_id( 'myaccount' ) ) );

		/* translators: Placeholders: %1$s - invoice number, %2$s - order number */
		printf( '<h3 class="order-info">' . esc_html__( 'Packing List - Order %1$s', 'woocommerce-pip' ) . '</h3>', '<a href="' . $view_order_url . '" target="_blank">' . $order->get_order_number() . '</a>' );

	endif;
	
	if ('invoice' === $type ) :	
	
		$view_order_url = is_admin() && 'send_email' !== $action ? admin_url( 'post.php?post=' . $order->id . '&action=edit' ) : wc_get_endpoint_url( 'view-order', $order->id,  get_permalink( wc_get_page_id( 'myaccount' ) ) );

		/* translators: Placeholders:  %1$s - invoice number, %2$s - order number */
		printf( '<h3 class="order-info">' . esc_html__( 'Invoice %1$s', 'woocommerce-pip' ) . '</h3>', $document->get_invoice_number() );

		/* translators: Placeholder:  %s - order date */
		printf( '<h5 class="order-date">' . esc_html__( 'Order Date: %s', 'woocommerce-pip' ) . '</h5>', date_i18n( wc_date_format(), strtotime( $order->order_date ) ) );	
	endif;
}
function sv_wc_pip_document_sort_order_items_key( $sort_by, $order_id, $type ) {
	// sort order items in all document types by SKU.
	// note: uncomment this line and remove the `switch` statement below
	 $sort_by = 'sku';
	// sort order items depending on the document type
	
	return $sort_by;
 }
 add_filter( 'wc_pip_document_sort_order_items_key', 'sv_wc_pip_document_sort_order_items_key', 10, 3 );

results: http://screencast.com/t/44jCjM8Hr8