It sounds simple enough - the Senate on Saturday morning approved a two-month extension of a payroll tax cut that is due to expire at the end of December. But did you know that the cost will fall on people who buy a house or refinance their mortgage starting in 2012?

Title IV of the bill is called "Mortgage Fees and Premiums," and what it does is to raise the fee that Fannie Mae and Freddie Mac charge to back home mortgages.

It would mean someone buying a $200,000 home starting in 2012 would have to pay about $17 extra per month - that's $204 per year.

The usual number used by the Obama Administration to talk about the payroll tax cut is that it gives working Americans about $1,000 per year in extra cash - except if you are buying a new house or refinancing, then you are going to lose around 20 percent of that tax break.

The fees charged by Fannie and Freddie wouldn't be done directly to homeowners, but to banks and other lenders; it would raise $35.7 billion over 10 years according to the Congressional Budget Office.

One interesting side note is this - instead of the extra money going to Fannie and Freddie to help the bottom line of those housing giants, which are losing billions each year - the money would go into the general Treasury.

When the idea was floated earlier this month by Sen. Bob Casey (D-PA), both the National Home Builders Association and the National Association of Realtors joined in a letter declaring the idea "counterproductive."

"Congress is essentially proposing to raise taxes on millions of potential home buyers in order to pay for a payroll tax cut and other non-housing legislative initiatives," said Bob Nielsen, the Chairman of the NAHB.

"With the housing market struggling to regain its footing, such a short-sighted move would be extremely counterproductive and threaten the fragile economic recovery," Nielsen said in a statement last week.

"That's exactly what the housing market needs right now," one House GOP lawmaker said sarcastically to me on Sunday night.

So, the increase in those housing fees would pay for a two month extension of the payroll tax cut ($20 billion), two months of extra jobless benefits ($8.4 billion), two months of a Medicare "Doc Fix" ($6.6 billion).

Early in my career as a reporter, I interviewed a local Chamber of Commerce official in Florida, who left me with a line that I have always remembered:

"What the big print giveth, the little print taketh away."

And that's very true with this two month payroll tax cut extension bill as well.

Some of you would get a continued tax cut - but those who decide to buy a new house or refinance their mortgage starting next year would see some of that tax cut taken back by Uncle Sam.