I upgraded from the 4Mbps to the 10Mbps plan a couple of weeks ago. Since then, I'd never had a speed test report more than 3.5Mbps. After reading this thread about torrents I figured I'd ring TCL and get them to check; sure enough, things were still set to 4Mbps. They fixed it there and then, and now I get over 9Mbps.
Great, but I shouldn't have to ring up again to get this done. As sbiddle observed, how many people are being ripped off because of incorrectly provisioned modems? We're used to the idea that consumer internet speeds aren't guaranteed to be what's advertised 100% of the time (thanks Xtra) - which is why it took me two weeks to ring up - but I wonder how many people just figure "that's what you get"?
Anyway, in short - it's worth the call.