Why does Audio to MIDI Inconsistently Convert Pitch?

OK...
 
Is this due to polyphony or some such?
 
I just easily dragged a bass track (audio) to a synth and it converted the part both pitch and timing...
Then I tried a monophonic (but stereo) guitar track (audio) and it only returned timing all on a single note...
 
Can someone explain what's going on?
 
I'm also guessing that I need to upgrade to Melodyne Editor (currently too expensive for me) to get polyphonic conversion or does it still not do Audio2MIDI for such?
 
Thanks!
 

But then why did it convert his bass track properly. I have experienced this same behavior. It works perfectly for bass, But I thought I'd create a midi flute part and played it on my guitar. It made a huge mess out of that. 
 
And I once tried to convert a snare drum audio track to a midi track and ended up with a bunch of notes all over the place even though I thought I'd changed to percussive mode. So it's just a bit buggy as far as I can tell. I don't care as long as it does the bass. I used drum replacer for the snare and that works great.