I partially agree.
However, I tend to ignore highs and lows when it comes to anything log related, especially if his average latency is 0, in my eyes the router is fine. But I just dont get how both his router is local and the 10.x is local. Who the fuck is 10.x! My guess is that 10.x is still the Cable Modem and its just subnetted so that it goes from LAN to WAN as all Cable Modems do. Very well could be they dont allow you to log in to the cable modem without defining the port.
A quick google search shows that many many cable modem vendors us 10.x for their local network. So that is where Im putting my money. Something awry with the connection from the router, to the cable modem. Now the question is, who is causing the issue.
Cats did you get a chance to unplug your router and connect directly to the cable modem yet? And the run that program? That is going to be the best bet at this point.