Deductions & credits

Thanks for your response.  That makes sense that I am being taxed on the value given to me - in this case my DPs health coverage.  Before I added her I was paying a $25 a month premium.  With her added the premium increases to $45.  I'm not sure what the exact tax on it would be in California, but if it was something like %40, and the value of her coverage was $523 per month, wouldn't I only owe the tax on that $523?  If %40 that would be about $210 per month which would mean $105 taken out of my bi-monthly payhcecks.  I don't understand how I'm getting a $274 deduction per paycheck twice a month.  If the imputed income is the value that I am receiving in the form of benefits, then why am I paying for all of it?  It seems like that defeats the purpose of employee healthcare.  I was trying to help my domestic partner and now I'm being deducted way more than she would pay for insurance out of pocket?  That just doesn't make sense to me.  Is there something key that I'm missing?  Thanks again for your explanation.  I'm trying to wrap my head around this and just feels like it can't be right.