So I finally stopped burying my head in the sand and went to H&R block with all of my documents. It was expensive ($120 x 4 returns) and they found I was owing for 3 of the 4 years. 2011 was netfiled but the previous three were sent by snail mail. That was about 3 weeks ago.
I got my 2011 notice assessment in the mail, explaining that they recalculated a bunch of stuff and gave me a
refund of around 4x what H&R told me I
owed (over the 4 years combined). I'm really confused and actually kind of freaked out, but I guess I'll have to wait for the other NoAs before spending this windfall I just received.
Kids: do your taxes the first time, on time, and every time.