I have incurred qualified taxes expenses for the American Opportunity credit for the past 5 years (2010 - 2014). I know the credit is limited to 4 years and those 4 years do not have to be consecutive. In one of those years (2011), the credit was limited to approximately $20 due to the phase out for income between $160 - $180K. In 2014, I would be eligible to take the entire $2,500 credit as my income is lower had I not taken the credit in 4 previous years. Can I filed an amended return for 2011, not taking the credit, and thus, make 2014 available for the credit? This way I forego the $20 credit in 2011, but pick up a $2,500 credit in 2014.