Domestic partnership: When state and federal laws diverge

On One Smoot Short of a Bridge, eeka discusses an issue straight married couples don't have to deal with: The federal government considers health insurance provided by one person as income for the other:

... I'm not even sure if we're supposed to base it on the premium; it just says "coverage." Are we supposed to declare the actual value of healthcare services utilized during the year as income? Or the value of healthcare services potentially available to us as a result of being "covered?" Do I need to go ask the assessor's office for the values of all of the hospitals in the region or what?