Arris 8200 Slow Gigabit Speeds

I upgraded to Gigabit internet several months ago and had lots of trouble getting it working.  Eventually a tech came out and dropped a wire directly into the room with the modem and now I have what I believe to be the strongest possible connection.  My internet rarely cuts out or has any service disruptions.  However, my internet speed has never gone much over 250 Mbps.  When I originally contacted Xfinity support they told me that often the speed takes awhile to kick in.  Unfortunately the speeds have never improved. 

I've done all of the steps in the trouble shooting guidelines.  What next steps should I take?