Hello datwoutes54, the information provided is correct. If you do want to add a premium channel or upgrade your channels let me know.
Thank you for reaching out to us. You would either need to call in to the 1-800-comcast number, or we can look at some packages for you. You would need to upgrade to a Preferred tier or higher if you have a Starter package.
You have to choose the package that contains the channels you want. You cannot add single channels other than premium channels such as HBO, SHOWTIME ect.