You're always more than welcome to add more meals to your weekly plan! In fact, you can order up to 21 meals weekly!
You can add meals to any scheduled delivery by visiting the "Upcoming page". From here, scroll to any week you would like to change, as long as the status of the order reads "scheduled" and not "processing", which indicates that your orders are locked are being prepared. Once you've scrolled down to your week of choice, click on "Manage Week". From here, you are able to change the number of meals you order for that week.
If you'd like to add more meals to all of your future deliveries, go to "Account Settings", then "Plan Settings". You can select your new preferred meal settings.
Make sure to click Save when you're done!