Part of this feel is due to the string through body bridge. When you bend, the part of the string behind the saddles (all the way into the body) also needs to be stretched,
Same with the part of the string that is behind the nut, which is why graphite nuts were invented. But this effect is more pronounced on the high E.
btw a string tree does not affect tension, but it does put more downward pressure on the nut, which could limit slippage.
the good thing about the VBT is that it has a 648mm scale lenght, shorter would be even bouncier:
http://www.jemsite.com/forums/f19/wh...l-82217-2.html