Those of you who follow the business side of football have figured out the formula that applies to the reporting of high-profile contracts.

First, someone reports the fact that the deal was signed. As part of the loose, unspoken quid pro quo that comes with “being first,” the reporter holds his or her nose and parrots the numbers that the agent is pushing, without scrutiny or confirmation. (Hey, if that reporter won’t do it, another one will.)

Second, at least a day or two later, someone else reports the true numbers, which almost always are less — and in some cases dramatically less — than the initial report.

Usually, the first report and the second report come from reporters who work for different news organizations. In the case of Donovan McNabb’s contract extension, the initial phony report and the accurate follow-up report come from reporters who work for the same company.

On Monday, ESPN’s Michael Smith reported that McNabb and the Redskins “have agreed to a five year extension, worth 78 million, 40 guaranteed.”

No one believed that McNabb was getting $40 million guaranteed. But since Smith and ESPN wanted to be first to report the news of the extension, they passed along the phony contract numbers on a don’t ask/don’t tell basis.

Now, Adam Schefter of ESPN reports that McNabb’s deal includes only $3.5 million in guaranteed money.

So Smith and ESPN were wrong, to the tune of $36.5 million. And now Schefter and ESPN are right.

McNabb can get another $10 million in the form of a 2011 option bonus, if the Redskins opt to pay it. If the team that decided to bench McNabb for Rex Grossman only 15 days ago decides after Week 17 that Donovan isn’t the long-term answer, McNabb will be traded or cut.

Beyond that, McNabb has non-guaranteed base salaries of $2.5 million in 2011, $12.75 million in 2012, $13 million in 2013, $13.75 million in 2014, and $13.55 million in 2015. The total base salaries for No. 5 over five years? $55.55 million.

He can also earn roster bonuses of $250,000 in 2010, $750,000 in 2011, $750,000 in 2012, $1.5 million in 2013, $3 million in 2014, and $2.25 million in 2015 if he’s on the active roster for each game in each year. That’s another $8.5 million. To get to that number, however, McNabb has to not miss a single game due to injury. In five years.

So it’s not a $78 million contract. And it’s not even close to $40 million guaranteed.

Usually, the puffed-up guaranteed money has some semi-plausible basis in fact. In this case, even if we somehow treat the option bonus as guaranteed (which it most definitely isn’t), Smith’s report is $27.5 million off.

It’ll be interesting to see how ESPN harmonizes these two reports. Actually, ESPN won’t even try, since there’s no way to harmonize these two reports.

Besides, ESPN finally has realized that, in the absence of conscience, it’s entirely possible to break the initial story of the long-term deal with the phony numbers, to follow up with the real numbers, and to then hope that 99 percent of the audience never notices the glaring discrepancy.