Are you saying that box 1a is $12.79? If the 1099-DIV is the only thing you omitted, you do not have to bother amending. You probably don't owe any tax on it at all. Even if it were taxable, the IRS is not going to chase after you for the tax on $13.
Are you sure there is nothing else on the composite 1099 besides $12.79 in dividends?
