IRS found some honest mistakes in my return

OK the IRS found some honest mistakes in my return-what type of penalty is involved?

You may have what is called an accuracy-related penalty applied to the taxes owing. The amount of an accuracy-related penalty equals 20 percent of the portion of the underpayment attributable to your negligence or disregard of rules or regulations or to a substantial understatement.

For individuals, the understatement of tax is substantial if it exceeds the greater of $5,000 or ten percent of the tax that must be shown on the return.