Save empty conditional fields with order in Conditional Woo Checkout Field Pro

functions.php

// Add this to your theme's functions.php file or a custom plugin.
add_action( 'woocommerce_checkout_update_order_meta', 'conditional_checkout_field_pro_update_order_meta_blank_entries_only' );

function conditional_checkout_field_pro_update_order_meta_blank_entries_only( $order_id ) {
	global $wpdb, $cwcfp_db_table;
	$fields	= $wpdb->get_results("SELECT * FROM " . $cwcfp_db_table . " ORDER BY id;");
	//Check to see if the checkout has been processed already or not
	$did_process	= get_post_meta( $order_id, '_cwcfp_did_process', true );

	switch ( $did_process ) {
		case 'processed':
			foreach ( $fields as $field ) {
				// The order was processed already, but did not complete, so we are deleting the old information in case it changed.
				delete_post_meta( $order_id, esc_html( $field->field_title ) );
				$id			= esc_html( $field->id );
				$quantity	= cwcfp_get_field_quantity( $id );
				for( $b=1; $b <= $quantity; $b++ ){
					$num_to_skip	= 0;
					$skip 			= (int) apply_filters( 'cwcfp_skip_first', $num_to_skip, $id );
					if( $b > $skip ){
						if ( isset( $_POST[ 'conditional_field_' . $id . '-' . $b ] ) && '' == trim( $_POST[ 'conditional_field_' . $id . '-' . $b ] ) ) {
							// Now we'll add the new information from the customer.
							add_post_meta( $order_id, esc_html( $field->field_title ), sanitize_text_field( $_POST[ 'conditional_field_' . $id . '-' . $b ] ) );
						}
					}
				}
			}
			// Indicates that the order has been processed
			update_post_meta( $order_id, '_cwcfp_did_process', 'processed' );
			break;

		default:
			foreach ( $fields as $field ) {
				$id			= esc_html( $field->id );
				$quantity	= cwcfp_get_field_quantity( $id );
				for( $b=1; $b <= $quantity; $b++ ){
					$num_to_skip	= 0;
					$skip 			= (int) apply_filters( 'cwcfp_skip_first', $num_to_skip, $id );
					if( $b > $skip ){
						if ( isset( $_POST[ 'conditional_field_' . $id . '-' . $b ] ) && '' == trim( $_POST[ 'conditional_field_' . $id . '-' . $b ] ) ) {
							add_post_meta( $order_id, esc_html( $field->field_title ), sanitize_text_field( $_POST[ 'conditional_field_' . $id . '-' . $b ] ) );
						}
					}
				}
			}
			// Indicates that the order has been processed
			update_post_meta( $order_id, '_cwcfp_did_process', 'processed' );
			break;
	}
}