The IRS alerted taxpayers and tax professionals about an interest calculation error on certain notices mailed the weeks of July 1 and July 8.

The IRS discovered errors in the CP2000 notices during a two-week period this July. The notices contained an incorrect calculation on the interest owed on proposed taxes from under reported income. The interest figures were lower than they should be. The IRS has corrected the issue for future mailings.

Later this month, the IRS will be sending a special mailing to the recipients of the notices. Taxpayers should follow the directions on the letter, and they will be encouraged to either call a special toll-free number or write to the IRS to receive the corrected interest amount.

A CP2000 notice shows proposed changes to income tax returns based on a comparison of the income, payments, credits and deductions reported on a tax return with information reported by employers, banks, businesses and other payers. The CP2000 also reflects any corrections made to an original tax return during processing.

Source: Special Mailings Going to Taxpayers Following Notice Issue