It's not a question of how long something takes to cook, it's (among other things) the job of the expediter to fire the orders to the kitchen at the right time so that they all come out at the proper time. If the lady’s risotto takes 30 minutes to cook, and the guy’s steak takes 10, then the steak should get fired 20 minutes after the risotto. That way, nothing sits on the slide for too long, and the order is garnished and ready for pick-up by the server all together.