That command line is correct.
If a package is already installed, it will tell you and won't reinstall it.
Admins monitor the forums, but are busy doing what they do.
We have bene using CWPpro for over 2 years, so if it's happened, we've probably seen it.
That being said, it's computers, and even some stuff doesn't make any sense to us either (works on every other server, except 1)