Touch movement, easing, tween to grid problems.

Hello, how are you?

First time here. I'm trying to figure some problems out here, but not much success yet.

In my game, player should be able to move a box (elevator) up and down, to deliver passangers in requested floors.

So, I have one major concern now is to find a way to control it nicely.

my 2 main problems:

I wanted to make the box go to touch.absoluteY position, but because of the parallax, the position don't match.

When player releases the touch, I want the box tween to nearest position, based on a grid.

Any idea?

dropbox.com/s/rf0baqb9kv2n0wh/01.capx