Year-Round Schools

I’m curious to know if there’s anyone else who’s being taken back to court to redo a custody agreement because one of their kids has been reassigned to a year-round school? My ex and I went to mediation, but instead of redistributing his four summer weeks that he currently gets, he decided he wanted 1/2 of all year-round breaks in addition to all the overnights he currently has based on traditional calendar (because we have two older kids on that calendar). He wouldn’t budge, so mediation was short. He already has more than 123 overnights after our first custody case three years ago. One of my kids is very opposed to more time with her dad. Anyone been there, done that yet???