Bracketing is usually done this way:
first round, no cross bracketing
second round, cross bracket
3rd round (quarters in 32 man) no cross bracketing
4th round (semis in 32 man) cross bracket

Alternate the cross bracketing every round

That is why in a 16 man bracket at state, the semis are NOT cross bracketed, because the round before that, the quarters, they DO cross bracket.

Correct me if I am wrong