Upgraded, like yourself, to IGB with AOL today. Just took your test. Downstream 903 Kbps (112.9 KB/sec) 975 Kbps (inc. overheads). Upstream 233 Kbps (29.1 KB/sec) 251 Kbps (inc. overheads).
I don't know anything about overheads apart from the fact I seem to have a lot of them.