I love threads like this because before I even read them 99.9% of the time I can just say it is the shub's fault

In this case though as much as it pains me to say it, the shub isn't at fault, either as a router or modem. Your power levels are good but for some reason you are having problems establishing a connection with the cmts. It is defo going to be an area fault and you need to ring tech support. They'll send an engineer out thinking the problem is your end but he'll be able to escalate it to networks and get it looked at.