You sure he isn't talking about digital bandwidth? Because that would make him correct. He can only talk about maximum throughput and theoretical bandwidth, he's most likely contractually unable to talk in actual download speeds in case your internet isn't fast. If he says you should be able to download at 20mB/s and you only get 9mB/s then you can complain to TW about not getting the service that you were told you were getting. If he only talks about bandwidth then he's covering his and TW's ass.