Effective March 31, the agency rolled out this program beyond the pilot stage, allowing all companies to sign up on a voluntary basis. Participants move from pre-CAP, which involves the resolution of all previously outstanding tax issues, through CAP, and eventually proceed to a less invasive "CAPmaintenance" program. Graduating to maintenance should generally come after "at least one or two good years of CAP," Dolan said.

"The first chapter's not yet been written on CAP," Dolan said. He added that, while the program is "important to taxpayers who are more or less concerned about predictability," it's important to keep in mind that companies should assess whether their corporate cultures are ready for the contemporaneous disclosure requirements involved.

"The business is entering into it, not the tax department, so the question is whether business and tax can partner in a way that one or the other is not left out to dry," he said. "It's not all hearts and flowers."