basically a chance for them to make sure their computers work. here a short blurb from the irs about it.
"The February date allows the IRS enough time to update and test its systems to accommodate the AMT changes without major disruptions to other operations related to the tax season. Although as many as 13.5 million taxpayers will not be able to file their returns until Feb. 11, the effect of the delay may be lessened by the fact that based on previous filing patterns only 3 million to 4 million taxpayers file returns with the five affected forms during these early weeks of the filing season.
The Feb. 11 delay caused by the AMT patch will affect any taxpayer using any of these five forms:
Form 8863, Education Credits
Form 5695, Residential Energy Credits
Form 1040A Schedule 2, Child and Dependent Care Expenses for Form 1040A Filers.
Form 8396, Mortgage Interest Credit.
Form 8859, District of Columbia First-Time Homebuyer Credit. "