Not quite the full story.

The problem is that you cannot rely on the "user" part of the path being @USERID.

For various reasons Windows will decide that the local version of the users profile is invalid or unusable, so it will create a new directory. A common cause is that you lose read / write permission to the directory.

Depending on the version of Windows, the new directory may include the domain name, or it may use an increasing numeric suffix, i.e. "jdoe.001".

The only way to know which one of the profiles really applies to the user is to rip the expanded path from the registry (or use %USERPROFILE%)