Amending multiple year returns: We filed 2015 returns and received refunds, but want to amend 2015, 2014 and 2013 returns for more refunds. What is the best way to go about it? Amended 2013 will affect 2014 return, which affects 2015 return. So, I am thinking of doing the following: 1) Amend 2013 to get the correct refund amount, which I used for amending 2014; 2) Do the same to amend 2014; 3) Do the same to amend 2015.
If this approach is correct, can I send them at the same time? Or does 2013 have to be there first, then 2014 and 2015? I understand that they have to be in separate envelopes. What should I do for state returns?
