K&K started recommended that exact placement, favoring the high E, a while back. The B string tended to be a bit too loud with the old installation.
I have a very rare K&K in my guitar. My high E was too quite (compared to all strings), so the luthier wired in a 4th head to the trebles side of the high E. My low E sounded just a bit too quiet when compared to the unplugged tone so... the luthier wired in a 5th head to the bass side of the low E. My guitar has a HUGE tone plugged in. Very full, very balanced. He charged me for what I got, 1 & 2/3 of a standard K&K. He said it was easy due to the vert basic nature of the K&K.
EDIT: I haven't read of the K&K being exactly over the high E like was suggested above. Last I saw it was just to be closer to the E as the picture shows.According to K&K's website, the transducer placement relative to the strings is fine
http://kksound.com/support/jig-new.php I find it pretty goopy looking, but I guess it's a lot harder to work on when you have to have your whole arm in there with no vision! If it sounds good, then it's good!