Both corporate and non-corporate taxpayers who have qualifying transactions may now be required to file Form 8873.
Audits of corporate taxpayers, however, edged up last year.
The telephone calls will be made to individual taxpayers on evenings and Saturdays and to corporate taxpayers during normal business hours.
Micron now employs more than 9,000 and is the biggest corporate taxpayer in Boise.
The rules changes proposed yesterday were announced after negotiations with representatives of corporate taxpayers, who have lobbied for quicker, more focused audits.
Preferences broadly available to most corporate taxpayers, valued at $68.7 billion.
"These two cases represent a shift in the pendulum back in the direction of corporate taxpayers."
It is the largest corporate taxpayer in South Africa.
One group is the large corporate taxpayer, and particularly wealthy individuals, who tend to have the most intricate returns.
Only corporate taxpayers can have the second type of adjustment.