adding additional licenses to existing profile

You should be able to add products to your plan. Can you share what type of plan you have and if you have purchased directly from Adobe or through a reseller. (You'll get this information from the Admin Console > Accounts tab). For Teams and VIP plans you can follow the instructions at https://helpx.adobe.com/enterprise/using/add-products-and-licenses.html

Let us know if I misunderstood your question. If you're seeing an error on the Admin Console, see if you can share a screenshot.