Mirfak is right. Technically it's your name etiquette that is off. The suffix "II" is only appropriate when there is a gap or non-linear relation between the second and the original bearer. I was taught that there need to be two generations between the first and the second, which has been the case in my family tree, but it might be a specifically regional tradition. Personally I find it incredibly ostentatious whether or not it's used correctly, but as the paperwork is already filed, perhaps you could settle for John Smith Sr. At least it's a more socially acceptable title.