And even the fairtax FAQ admits it, if you bother to read down to Question 47...
47. I know the FairTax rate is 23 percent when compared to current income and Social Security rate quotes. What is the rate of the sales tax at the retail counter?
30 percent.
"Show me just what Mohammed brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached." - Manuel II Palelologus
Try to understand the difference between an inclusive tax and and exclusive tax. I knew this was what you were going to present and it is thoroughly discounted in #47 of link you provide. Read it and try to understand the math. Clearly, you don't undestand the difference between an inclusive tax and an exclusive tax. This is where your misunderstanding lies.
BTW, Wikipedia is a very questionable reference. Surely you've heard about all the lawsuits that have errupted because of false information being posted there?