One of the inherent problems of a sub satelite system is frequency humps and frequency holes.

It's my understanding that frequency humps are more noticable than frequency holes, and for that reason, designers may tend to not want to make the high pass crossover and low pass crossover exactly the same, since that might cause a frequency hump.

Better to have designed-in fequency hole instead than risk having a frequency hump.

A sub-sat system with a hole sounds pleasing, until compared against a full range system. The rull range system sounds better.