W2 Box 12 Code H

[Randall]

Client has Code H in Box 12 of W2.  Looking at this appears to allow a deduction to AGI on line 36.  But the W2 summary is showing this amount deducted as a pre-tax deduction with the reduced amount of income in Box 1.  Client says he is entitled to the deduction and others at work have been doing this for years marking line 36 with 501(c)(18)(D).  It appears to be a double deduction.  Has anyone encountered this before?  I could see the line 36 deduction if Box 1 included the amount to begin with.  Could it be their HR people are coding this incorrectly?  Or are they entitled to the additional deduction.