does your state have an online formula?

here it includes who's carrying insurance, and real time spent with each parent.

i'm proud of you for addressing this with him. don't let this slide. and don't take his word for it. do a consult with a lawyer to know what you're really entitled to. there will be additional expenses, like driver's ed, which was $1k back 5 or 6 years ago, prom, etc.