Func_plats are evil! Don't ever use them!!!!
Here's what I do:
First off, make sure you have both JKII Editing Tools 1 and 2.
(This is how to make an elevator that's going to go down)
1) Now, make a brush that is going to be your elevator. Now, deselect it. Don't do anything to it yet.
2) Place a ref_tag on one corner of the platform and targetname it "elevator_up". Place another ref_tag in the same corner but drop it to the place you want it to stop below. Targetname this tag "elevator_down"
3) Place an origin brush (that's a normal brush with the origin shader) in the same place and the same size as the ref_tag named "elevator_up" (where your platform is). Don't worry about it being inside the elevator brush.
4) Now, keep your origin brush selected and select the brush that's you'r elevator platform. Right click and make them a func_static.
5) Press "N" and add a soundset with a value of "impdoor1" or whatever. Here's the important part! script_targetname it elevator1!!!
6) Now, add a trigger_multiple near the elevator where you'll be walking to it and have it target a target_scriptrunner. Select the target_scriptrunner ONLY and hit "N". Under key, type "usescript" and under value, type "elevator1_script".
7) Add lights and compile. Close JKIIRadiant and open BehavEd. Add the following lines to your script:
affect ( "elevator1", /*@AFFECT_TYPE*/ FLUSH )
move ( $tag("elevator_down",ORIGIN)$, $<0 0 0>$, 4000.000 );
wait ( 6000.000 );
move ( $tag("elevator_up",ORIGIN)$, $<0 0 0>$, 4000.000 );
Save it and compile it as "elevator1_script" under the scripts directory.
Remember, you script_targetnamed the func_static "elevator1". This script affects it and tells it to wait 1 second, move to the ref_tag named "elevator_down" in four seconds, wait four seconds, then move to the ref_tag named "elevator_up" in four seconds. The tag named "elevator_up" is placed in the original resting position that the elevator was found in. Get it?
It's a bit more complicated than using a func_plat, but it'll get easier. Plus, this makes a two way elevator that doesn't wait nor care if the player gets off or not.
To make an elevator that goes up and then goes down, reverse the process.