Some codes affect your current year income tax return, and other codes are simply for your information. Here is the detailed list of what can be entered:
https://ttlc.intuit.com/replies/3300234Did you ever figure this out? I’m dealing with the same problem now.
Any codes on the W-2 are the responsibility of the employer (or the company they hire to do payroll) to figure out. The taxpayer should generally just enter what the employer puts on the W-2.
Having said that, the employer sometimes gets it wrong.
Since I don't believe that any of the codes for box 12 on the W-2 are appropriate for the Aflac plan, I believe that this amount should go in box 14.
Only a few Box 14 codes are defined; these codes are largely determined by the employer to communicate something to the employee.
In any case, the W-2 is wrong if the Aflac premiums are coded with a code of W in box 12, and you will have to ask for a corrected W-2. Have your employer read the Instructions for W-2 and W-3 at the IRS website.