Hey all I recently purchased a very nice 2010 Birdsong Corto and am a little confused about the controls. it seems to have a volume knob for each pickup and a varitone switch. The volume controls interact differently depending on the switch position. when in thebmiddle position the neck pickup volume seems to boost at about 80% with the bridge maxed. Once past 80% the volume drops alittle. Any pointers would be great. The bass is awesome and has made me a convert to the birdsong line.