cPanel packages and additional disk quota

Hi What is the best practice in this situation: We are selling a hosting package, let's call it "Package A". Package A has 20 GB of disk space. We are also selling additional disk space in blocks of 1 GB. So we might have a customers: - Customer 1: 20 GB (from the Package A) + additional 10 GB = 30 GB total disk space - Customer 2: 20 GB (from the Package A) + additional 5 GB = 25 GB - Customer 3: 20 GB (from the Package A), no additional disk space - etc. You get the picture. There's two ways how to handle this situation as far as i know. 1) Modify the customer's cPanel account directly and add the additional disk space 2) Create custom-package of Package A for the user and modify the custom package. So we might have packages: Package-A, Package-A-Customer1, Package-A-Customer2, etc Both ways are making life hard in the future. For example if we need to make a change to the underlying package. In situation 1: If we make changes to the Package A which all the users has, all the changes goes directly to the all user's accounts. So they loose additional disk space for example. In situation 2: If we make changes to the Package A then we need to make same changes to the all custom-packages as well. Please tell me there's better way.