Lets say we have a folder A linked to FTP User A. This client has full access to this FTP folder. This FTP (A) has another user B. A does not want B to have access and see all that is within A's folder, so A creates a folder for user B and would like another account to point to B's folder so B can only see and access his folder.
In this case yes, each one of them has a quota limit. I believe this will give quota problems between them.
In this scenario I believe it would be best to calculate the current quota from the folder size and not from what the client has uploaded and deleted, unless there is another way around this that you could advise me on.