I need to file an amended 2011 NJ state tax return due to a missing 1099-int for about $1100. I also had to change to a property tax deduction vs property tax credit. Don't know what the accountant was thinking. I now owe $59 additional. How do I calculate the penalty/interest for this situation? Do I have to pay the penalty for late filing or just late payment + interest?

I took care of my federal amendment and for that they calculate the penalty/interest. I redid the state I worked in as well (NY) and I'm actually receiving a bit more refund. Just not sure how much to pay NJ.

Thanks.