In a complex federal system, determining how much taxpayers owe to each taxing authority requires not only careful calculation. It also requires proper application of the law.
When people in Southern California think of an Internal Revenue Service audit, they may picture an agent grimly scrutinizing a taxpayer's Form 1040, inquiring perhaps whether the person was eligible to claim certain deductions. While the IRS does perform tax audits of individual tax returns, it also spends a significant percentage of its resources on examining the returns of corporations.
It seems fair to say that no one is entirely happy with the American corporate tax code. It is also fair to say that many people who deal with the corporate tax code hate it passionately. One of the biggest problems with the code is an aspect of it that corporate America might be the happiest with: it is constantly Changing as a result of successful lobbying by corporations to have new tax breaks inserted into the corporate tax code.