Just an update - our provider made the requested configuration change (to duplex autonegotiation settings), and we've made matching changes. We should have slightly more available incoming (download) bandwidth, and the outbound connections should be substantially better. We think that may have been the cause of the WoW behavior you were describing.
Please let us know how it's working. I realize that Friday through Sunday may not be the best time to check - Sunday and Monday night are more "typical".
We may continue to make additional changes as we monitor how things are working - we're going to attempt to make the most out of the connection we have. At the same time, we are pretty close to the limit on our incoming connection, so there's a limit to how much better it can get.