My real download and upload speeds (measured here) are always about 1/3 of what the Time Warner Roadrunner speed test shows. Their results at times have told me my service was fine when in fact there were signal problems at their amps outside. They and most ISPs advertise falsely. The only thing you can say is that they typically deliver their promised rates as measured on their instruments. When you read the TestMy explanation, all this you will have a better understanding. The reality among many ISPs is that they (as a business) know they are advertising falsely, but each one is advertising not any differently than most other ISPs, so they feel there's a built in immunity to legal action because everyone is doing it. Some are undoubtedly worse than others. In your case, if they "guaranteed " you 20MBPS down, and you're getting 10, you're better off than I am. The only way to fight all of this would be a class action lawsuit. The only solution would be to create a set of specifications for speed measuring (similar to what they did with audio power amplifier power measurements). Then an ISP could either be compliant to the spec or standard or not, and the buyer could decide if he wanted to go with one that didn't claim compliance, or one that did. Right now it's a mess. I don't know if the typical support person you talk to knows anything other than the tools he was given to measure speed at that company. If he/she does know, they're between a rock and a hard place, because they can't tell a customer that their tools are wrong.