LEP isn't really the same thing as a Lateral Transfer (even though the end result is similar). LEP is an education program. You can apply anytime between 2 and 6 years of active duty service, irrespective of your aviation commitment.
In reality, because aviators start getting quality competitive fitness reports later in thier careers than SWOs, Supply, etc., they aren't competitive for LEP until close to the end of the eligibility window, if at all.
Regarding the aviation commitment, your payback clock stops rolling while you're in law school, and gets added on to your LEP payback. I'll have about 17 years in by the time both my commitments are satisified (forget about any bonuses from either community).
I got picked up for LEP at the end of my first sea tour (about 3.5 years after wings, and just under six years active duty). I got lucky -- most pilots don't have competitive service records until after the six-year mark, when they're no longer eligible for LEP.
It's a long shot, even for SWOs and Supply weenies who get a chance for more LEP looks than pilots -- like I said, I got lucky. I would never recommend it as the preferred course of action to someone whose ultimate goal was to become a JAGC officer rather than URL. But it is the best deal in the Navy, so if you're interested, give it a whirl. The worst thing they can do is say no.
Grain of salt: all of my info was accurate as of the time I picked up LEP (April 2002). The Pers-4416E detailer can provide up-to-date info.
