I saw Indiana beat 6 AP top 10 teams this year. They had previously beaten 10 AP top 10 teams in their history.
Not sure if thats true, but I saw it on the internet.
I also get that 4 of those were in CCG/CFP games, that didnt previously exist. But in that era, they probably would have played OSU in the regular season, instead of a CCG, and I guess Oregon in the Rose Bowl, instead of the semifinal. So its still 4.