I really appreciate your help but we seem to be discussing things differently.  

Here is my example and maybe someone familiar with CA RDP taxation can weigh in.

Gross Pay = $5,000

pre-tax health for employee $500  (saved tax)

net federal taxable income  $4,500

payroll taxes withheld on $4,500 of income = $2,000

post tax payroll deduction for CA RDP health insurance  $300  (does not save tax but if this was a spouse, not a registered domestic partner  it would have been pre-tax)

net check $2,500

For CA same net check but the $300 was not supposed to be post tax.

W2 has same taxable income box 1 and 16

California affords the same rights to registered domestic partners as to married individuals. As such, amounts spent on domestic partner healthcare is exempt from California taxes under Revenue and Taxation Code section 17021.7.