Please note that although matchmaking in BH does try to match close to your hall level, it also has to match with a base close to your trophy level. Also, the opponent has to be live and searching for a bh battle at the same time.
I think the combination of these criteria are what makes matchmaking in BH like this-sometimes you get matched with someone two halls higher (rare but not unheard of) but they are ultimately close to your trophy count.
Even in main village this occurs in certain leagues for a particular th level. But unfortunately you don't have any option to next in BB unlike in MV.