There are many reasons for pkt loss, and while one of the upstream channels is a bit out of spec, there may be more to the issue. A tech onsite is the best solution. The Cox Complete Care, is kinda like insurance. It's good to have when you need it, but you always hope you don't need it. It covers the cost of a tech out, IF the issue is something that would be billable. The line inside your home, from the demarcation point outside to your modem, is what would be billable if that's where the problem is. If the problem is your modem, again, billable, and CCC would keep you from having to fork over 75$. If the issue is delivery of the service UP to the demarc, that's Cox's responsibility, and they won't charge for repairs if it's on their side.
I hope that takes out some of the mystery.