dmertz, thanks for noticing this, especially since I quoted you - yes, you're right it was (correctly) in Box 2 for 2017, not Box 1. I only made the one contribution during 2017 and it was counted toward 2016, but listed on the 5498-SA for both years, in different/appropriate boxes. So I did the subtracting and entered zero in TT for the contribution made in 2017, based on your previous answer to the other person. That makes sense, but I wish it was spelled out more clearly on the forms 5498-SA.
Would it be advisable to enclose an explanatory note, or is the IRS used to this and will figure it out without my help? Seems like less is more with them....
