"Advanced Hosting Nameservers If the domain for this website is registered through us, we will automatically configure your domain to work with your website."
...But you offer this service only once? Both my current main domain (flagmob.org) and my intended future main domain (spinyourworld.com) are both registered through you. I couldn't find any documentation stating (or, warning) that once a domain was configured to advanced hosting, that this action is permanent.
A cursory google search tells me that this change is possible at other hosting companies. Surely there is some way to change the main domain, while retaining all the files associated with the old one.
If you add new domains to your hosting plan, you can set the Name Servers yourself. Our system doesn't have the ability to "see" the Add On Domains inside your CPanel account.
My domain is registered at Dynadot and I also use your Email plan. How do I configure my domain to my Email package?
To use your Email plan, please follow these steps: