In order to apply the add-on to your current subscription, please follow the steps below:
1. Go to the “My Account Dashboard” on the Home tab of your Customer Portal
2. Scroll down to see Power up your Subscription, choose the add-on that you'd like to purchase for your current subscription and add to subscription.
3. Tick both boxes and click 'add bundle'. You will be immediately charged (creating a separate invoice for the add-on) and the changes will be applied to your remaining boxes.