I have never listened to my strings while pulling on the whammy bar. That may be how it works... They are all different strings and aren't gonna stretch the same way (i would assume). I don;t think whammy bars are for accurate pitch bending they are for funny tricks and cool screams and such.

I don;t use mine much and personally I think it causes some problems, but damn am I glad I have it when I do use it and then I go right back to using it was a fixed bridge... I can never turn my amp up loud enough to really enjoy it thats the problem.

I could be completely wrong, you don't really have to listen to me.