The leaves are likely to break where the old holes are (or were). Your flex won't be as good as before since the axle isn't in the middle of the spring where the spring rate is lowest and the travel is "most-est."

I'd say you're far better off just running some decent shorter springs.

'97 4Runner, '06 F350, '86 4Runner, '05 WR450
http://home.4x4wire.com/erik