You still don't get it. Yes FICA is a separate category. However under the current tax code you owe a certain amount of FICA taxes at the end of the year. Unless they change the rate: (which they have not by the way) it is NOT a TAX decrease.
At the end of the year when you or your accountant are doing your taxes you will still owe the same amount for Federal and FICA. If they didn't take out enough, guess what? You will have to PAY, or you will get a smaller refund.
It’s you that don’t get it amigo. The FICA rate for 2011 went from 6.2% on the the first $106,800 of income to 4.2%. For those making $100k, you saved $2k. It’s got nada, zip, zero to do with income tax. For those making $100k who have any brains, the 2% rate cut was offset by a 3% increase in their 401k contribution. My takehome went down about $300 this year, but I have $3,000 more contributed to my 401k. If my portfolio would do that earning thing, I’d be in great shape.