I just went through a very long (about two months) trouble shooting session with Charter after moving to a new town. After getting the personal cell phone number for a local plant supervisor and keeping in touch with him during the time it took to fix things I got some information out of them. They try to keep their lines at 80% capacity all the time. They do have traffic shaping in place though he wouldn't be specific or didn't know. They don't throttle customers, they do disable power boost and more tightly restrict bandwidth to the plan the customer uses during peak hours. Which tools they are using to manage these restrictions I don't know.

Since they've finished the DOCSIS 3 rollout here last week I've considered upgrading to 60/5 from my 25/3 plan but it's pretty over priced and would be much more worth it at 60/10 or 60/15. During the period of trouble (not enough bandwidth for their inter city link where they actually do their peering) I was down as low as 1Mbit/s during peak hours on a 25Mbit plan.