I can't tell if you are serious enough.. there's no way Comcast is going to run a dedicated line for you for $200/mo. The only reason I can see for the increased price is it means they can fit less people per node, so they end up needing more.

I was joking.

There is no rational explanation. Some people perceive the highest price as being the best.

Relevant discussion here:

http://news.ycombinator.com/item?id=2640685