Question about old case -1990's

I hope someone can give me an answer. Back in the mid/late 90's I took my daughter's father back to court to have her placed on his health insurance. The hearing examiner did this, however she reduced his obligation amount to reflect what he paid for the premium. Anything not covered was prorated between us. My current fiancee now tells me that should not have been done , that he should have been made to pay the full amount. Looking online, I can only find info on this from the last few years. Nothing I can find goes that far back. I hope I am not finding out now that I was treated unfairly - btw, we are in New York State. Answers???