I got it working the trick is small steps.
Elevator at the top set key frame 0
Still at the top advance counter to 400 and set
Advance key frame to 405 and move elevator down -.55 and set
Advance key frame to 410 and move elevator down -.55 and set
Advance key frame to 415...
I have been playing with the model you sent and it is very odd indeed.
I don’t think I have ever seen this or I just have never noticed it before but it sure wants to float up and the top and again it moves oddly at the bottom.
I remade a very simple test object with a few marker...
All I wish to do is to see if you have the paths set correctly to the compilers and to see if they are working.
All I want you to do is make a cube 200x200x200 and set origins to the bottom and compile as Scenery BGL.
Install this BGL into any active scenery folder and then go...