Batch Invoice Printing for Wordpress with WooCommerce

We have an e-commerce website running WooCommerce on WordPress. We have a plugin installed called WooCommerce Print Invoices & Delivery Notes. This enables us to print invoices of our orders. Currently, we can only print one at a time. We need someone to modify the plugin so we could select any/all orders on a page of orders and print all at once. This should be extremely simple--it should take less than an hour and cost $10. The only complication is that our site is live with ~4000 users, so you must be certain the code is correct before uploading anything to the server.