Been working at this for a few weeks. comcast (logon/services/device mgr/data bar graphs)(hover mouse over bar graph to get current tot use) it will frequently say something like a 20GB use in a day, where the A7 says about 9GB. Wondering if anyone can give me a clue to why the difference? Of course called comcast many times but get either brush-off or "we are right and your router is wrong"  type answers.

No wifi - wifi is turned off. 2 wired devices: laptop, and firestick 4K. Just discovered that firestick also monitors data use and initially seems to match A7 stats but need a day or 2 more. Did a test download of a 2.2GB iso on laptop and that showed correctly in A7 stats. No hotspots per comcast.

Any clues?

Thanks!!!

EDIT: cable modem new Netgear CM500