[Mark Dexter]

I don't know about NIT, but NCAA is pretty straightforward:

Conference assignors submit a list of their officials, which are listed by "rank," so to speak.

Each automatic qualifying conference is guaranteed at least one official to be "in."

96 officials (32 games/crews) are selected for the first round. The referee from one game will act as the alternate for a specified other game. 48 officials (16 games/crews) are pre-selected (i.e., at the same time as the 1st round) to work a second-round game. In order to work a 2nd round game, the official must have been assigned (floor or alternate) to a 1st round game). These assignments are by individual, not by crew.

Any official working a First round game is then eligible for an assignment to the regional. 36 officials (12 games/crews) are selected - 3 at each regional site (regional semifinals and finals). An official would only work the regional final or a regional semifinal.

Any official working at a regional is then eligible for a Final Four assignment. 3 crews are selected (1 for each Semifinal and for the National Championship Game), plus one alternate (covers all games) for a total of 10 officals.