Service Oversold in Irvine, CA. CMTS response time fluctuates wildly

It appears that Cox does not have the infrastructure to support usage at peak hours near my location.  This results in highly degraded service in the afternoon until later at night.  Some investigation strongly suggests that what I assume is the CMTS is badly overloaded.  These results were taken around 7:00pm.

When attempting to talk to Customer Support about this, they insist on just resetting my modem, and talking to anyone with any knowledge about the subject matter seems impossible.

If my service is going to be degraded, and indeed unusable for several hours a day for anything response-time sensitive, then I expect that I should be paying a 'degraded' bill...