Each ACC team plays the 6 teams in its division, its protected crossover, and one rotating team from the other division every year. So each ACC team will have 6 conferencemates that it will play each once every 6 years, at home once every 12 years.
Pitt plays FSU at home this year, but won't see the Seminoles again in Pittsburgh until 2025. They'll play in Tallahasee in 2019.
The commissioners will rue expansion someday. It's poisoning the entire college athletics system.