(As a footnote i personally dont think bi wiring does much of anything )
I've never explored this but here's my thinking on bi-wiring ... if your speaker wire size is marginal the current draw of the woofer may effect the waveform distorting the higher frequencies. By bi-wiring you can eliminate that distortion.
It is one reason I like to see a wire resistance less than a hundredth of the nominal speaker impedance.