Yes, you can have multiple subscriptions under a single Norton Account. This would mean that the subscriptions are separate and not in any kind of sync with each other. The easiest way to do this would be from within your Norton Management Account:
- Log on to Norton Management.
- Click the My Account tab.
- On the My Account page, click Product Details.
- Click on the Norton product for which you need additional product keys.
- In the Manage My Installs section, click Buy A Key.
- Follow the on-screen instructions.
Alternatively, if you have a chance to buy Norton 360 subscription at the price lower than the price of buying an additional key through your Norton Management Account, you can simply buy it as you would buy the product for the first time, and have that subscription as an additional one in your Norton Account.