All joking aside, the numbers look to be way out of whack. Six dollars at 6% would double in 12 years. The late payment penalty of 0.5 %/m maxes out at 25%. There one of two possibilities; the amounts were miscalculated; or, they are related to something else, such as estimated tax penalty.
Before doing anything else, I suggest that a copy of the Account Transcript be obtained for that year. The transcript will show what the penalty is for and when it was applied.