one 843 for everything for any single tax year. whether interest can be abated depends on the facts and circumstances. for example, you are charged an underpayment penalty. you ask for abatement because you have reasonable cause. the IRS can abate the 2210 penalty but not the interest. If the iRS imposes the same penalty but is in error in that you don't owe the 2210 penalty then both the penalty and interest will be abated
