DW and I are over the limit and are suppose to participate in AMT. What I do instead is check "married but at the higher single rate" and also withhold additional $ each month. Is that acceptable? The IRS is getting their fair share (and a little extra) every month. I miscalcualted a bit last year and received some cash back. I have adjusted withholding so should be right on for 2017. So the question is: Will I get in trouble for not sending in quarterly AMT payments despite withholding plenty each month?