@ASAJAY
Just a guess ... did you mail in the return? IF so the data entry person at the IRS is probably to blame since line 15 is a calculated amount which is automatic based on entries on lines 12a&b. Always efile when possible ... same goes for your son. Missing withholding was either a data entry error by the IRS or his failure to attach the paper W-2 to the mailed in return ... without that paper document to support the withholding claimed the IRS will disallow the entry.
