Kevin;

Lets think about this for the moment;
If Mains set to small fc = 40Hz
Center set to small, fc = 80Hz
Rears set to small, fc =160Hz

The subwoofer has to receive one of the three fc's above. Theoretically, it should receive the highest fc to eliminate any bass gaps between the speakers.

I really don't think multiple crossover settings for each speaker is a good idea and I agree with the review in doing so, try to keep them within 20Hz of each other, if not all set equal.