I could be wrong but I believe in the crossover games (1st round) they usually use a team of officials form the home conference.I would suppose due to travel expense. I dont beleive there to be rule in a book about it, I would think it would be a decision made by the collective group of athletic directors from each district. And then when the tournament gets to one location (2nd round and later) you will see a mix of east and west officials working the games. From what I have seen there is a big difference in how officials from different conferences call games. (not saying better or worse, just different). Thus getting home court advantage for the first round is very important, as after 20 games a team should have a pretty good feel on how the game will be called. I think your more experienced teams are able to make adjustments early in the game, dependent on how the game is being called. I'm pretty sure the officials in Zillah last night were all guys i have seen work the west this year. And for the record i thought they did a nice job. I'm sure Connell was called for more fouls than Zillah in the game. But Zillah was quicker and more aggressive to the hoop which was causing Connell to foul.