It’s been my experience that no two IRS agents follow the same rules. It’s pretty much a rogue organization, like the BATF. After all, who’s gonna stop them, Eric Holder?
You are correct to point out that Eric Holder would likely be disinclined to stop any Obama administration agency from doing anything it pleases. But Holder, who would have authority over BATF (which is part of the Dept. of Justice) does not have direct authority over the IRS, which is part of the Dept. of the Treasury in the bureaucratic organizational chart.