They actually call them "First Four" games, not "play in" games, and the round of 64 is called the "Second Round." At the same time, everyone calls them play-in games. But those same people call it a field of 68. If it's a field of 68, they aren't play-in games; they are first round games. Mathematically, if you have a 68-team tournament, you give 60 teams first round byes to make the numbers work out.
If they are play-in games, then it isn't a 68-team tournament; it's a 64-team tournament with four games to determine the last four teams in. The NCAA needs to make it clearer, and journalists need to get it straight.