No it isn’t doubling your traffic in the latest version of avast 9.0.2011 on win7 avast intercepts calls to http connections and it handles the http traffic so that it can be scanned before you view it in your browser or download it.
Consequently you will see connections for avastSvc.exe but you will see much less for your browser. You have your browser connect to a site, but that connection is intercepted by avast and it deals with the request.
Thanks, I believe I see that is what’s happening now that I look closer, I see the Avast service receiving from a remote site, and sending to the local computer name.