Software Deployment

I just about went crazy on my first software deployment from "Access Denied" messages until I found this article. I had to use both Copy and RunAs in order to get a successful install. But now I have the following questions:

1. Why must I specify RunAs when Desktop Central already has the same credentials stored under Admin > SoM > Edit Credentials. They are exactly the same credentials. Should not Desktop Central simply use these credentials by default?

2. Why must I specify the MSI Root Path? It is identical to the MSI File Name with Network path.

3. When modifying an existing configuration there is a link for Add Package (which really means create a new package in the repository) and another for Add More Packages (which means add another package to the current configuration). This is very confusing. Could these labels be clarified?

Thanks!