New client hasn't filed taxes for 10 years. Single, W-2s only. No dependents. Have explained no refunds for anything before 2017 will be issued.  Question is would any refunds and or amounts due for those years be "balanced" out?  Example  2011 refund 100 and 2012 due 100 would the IRS balance it to 0?  Also is it still required to mail each year individually or do a packet with all returns?