There could be routing issues which would affect different routes at different times, it could be at your ISPs end, or D* providers end (AT&T in this case), or any router that is being used at that time between your ISP and D*s site, since routing is dynamic, this can change at any time, in networking, any given packet exchange can change routes from time to time depending on the network traffic and the condition of any routers in between. This can be exasperated by any use by D*'s site to load ads or images from 3rd party servers, or other crosssite or backend (remote db access) activity which would affect D*s sites apparent loading time.
Comparing one site against all others does not tell anyone much other than they are having issues of 'some kind', since routing is dynamic, in order to narrow down where the problem lies, a traceroute should be taken at the time of the occurance of the latency, if that traceroute shows nominal latency and 0% packet loss, it can be assumed that the latency is probably caused by D*'s new site, perhaps inefficient scripts, high load, etc.