I would agree that if you reduce communication frequency, there is less chance of network software, firewalls, proxies and routers actively preventing communications.
That said, server side restrictions might still limit your network communication to working hours. If you do reduce the communication frequency, you will be able to look at the logs and work out if that is the case. If Boinc does communicate with the WCG Servers, out of office hours, then such server restrictions are not in place.
It might also be a good idea to look in every day or two and check to see if there are tasks ready to report. If there is update them, under projects tab.