dales (programmer) 18 September 2010
Can happen anytime. Ours happened 2 years after the year we filed. We found out when they sent a bill for $900.00 which included the additional tax due that they felt we owed and lots of interest and penalties for the 2 years that we didn't know that anything was wrong. You have to dispute it and prove your case or pay the money. It's not easy to prove your case with the IRS, we were however successful, but I have an business accounting background.