In preparation for my 2018 filing I went thru my 2017 and found out I accidently increased my federal tax W/H (Box #2 on the W2) amount. Myfinger must have hit the 5524 instead of 4524. I mailed it in last April and till this date have not received a CP 2000 notice. The IRS computer system must match withholding amounts so I'm wondering if I should wait or when mailing in my 2018 form also turn in an amended 2017 1040X?
suggest putting them in separate envelops but certainly file the 2017 1040x asap