I don't see your Acrobat licenses there in the dashboard and you are correct that assigning the complete plan would use up one of your licenses.
It may be that you have a separate serial number for Acrobat. To check this you would have to go to the Adobe Licensing Website licensing.adobe.com and log in to view the licenses under your account.
If you are not sure about how to access this website I would advise opening a case with support and they can check your licenses.
From the dashboard go to Support and click Open a Case. Your phone support number should also appear.