Frederick failed to file his 2018 tax return on a timely basis. In fact, he filed his 2018 income tax return on October 31, 2019, (the due date was April 15, 2019) and paid the amount due at that time. He failed to make timely extensions. Below are amounts from his 2018 return: Taxable income - $120,000; Total tax liability on taxable income - $28,346; Total tax withheld from his salary - $25,000. Frederick sent a check for $3,346 in payment of his liability. He thinks that he has met all of his financial obligations to the government for 2018. For what additional amounts may Frederick be liable assuming any applicable interest rate is 6%