I would question your skills too...
If you have packet loss to your modem, anything beyond that is irrelevant. Who cares if you have packet loss further down the line - of course you will have packet loss further down the line.
Sounds like another self-proclaimed know it all that the Comcast tech called BS on.
Wow Wirelessdog, you are SUPER helpful. The modem problem is new since the replacement of the old modem. They came and replaced the "new" modem and found out there was a line problem in two places.
But hey, take your A+ cert and go become one of them tech's. Good luck buddy.