Because Zwaloo is low pass filtered and inverted, combining it with Zwo creates a high pass response of sorts when the cross fade is within a certain range - so its higher frequencies fade in first over the top of low passed Zwaloo. All the way CW, you have Zwaloo, all the CCW you have ZWO, and throughout the middle you have a crossfaded, quasi-high passed mixture of Zwaloo and Zwo. Note that Goofy is only included with Zwaloo, so the more Zwo, the less Goofy. Make sense? If it does, you are either in need of some serious help or have earned an honorary degree of Wackology =-D.