Ok, think about this. The clans wouldn't all have the same hunting schedule or planet would they? Anna tells them "only in the hottest years this happens, and this year it grows hot." It would seem that the Preds have visited that particular area several times over untold years, not every century, and not the same Preds. The hundred years thing is probably only for the blooding ritual hunt. They are supposedly drawn to heat and conflict. That means anywhere those two things combine. The heat for the Pred's comfort and conflict so that he can test himself against seasoned fighters from other species. The Pred in P1 was drawn to the heat of the jungle and the conflict between the rebels and whoever they were rebelling against. Harper's team was sent in and got caught in the middle, and Arnie's team did the exact same thing. That's probably why the Pred stayed, so he could collect more trophies since the Green Berets and commandoes were more challenging than the "half-ass mountain boys" as Arnie calls them. If he had killed Arnie's whole team, he probably would've left. That's the way it seems to me.
