"is his normal compensation and does not include health insurance premium and he seems to be right based on the fact that boxes 1, 3 and 5 of the W2 are the same."

Well, that's not very well worded, to help you.

It could be that they pay his insurance from his base pay and he doesn't even realize he is paying with Post-tax dollars. In other words, this is not an additional fringe paid by his employer; they are "doing the banking" by making his premium payment, most likely because it is under their group plan.

"I have talked to the S Corp filer accountant before and he is a little defensive."

We simply need to understand the employer's benefit package. It might be really simple.

You earn $120,000 a year gross.

We compute taxes.

We then deduct for your health insurance.

You get the difference = your take home.