It seems like several things could be wrong with that W-2. The difference of $3,450 between the amount in box 16 and the amount in box 1 seems wrong relative to code W amount (for a California resident).
What is the code in box 12a for the $18,500? I'm guessing that it's code D for an elective deferral to the S corp's 401(k).
Is the S corp owner a 2%-or-more shareholder in the S corp? I'm guessing Yes because the S corp health insurance amount has been included in box 1.
Does the $12,545 of S corp health insurance include the $6,900 HSA contribution?
