Animate movement based on scale

I have a door that opens vertically with an animation that changes its y to -6 (the door has a y scale of 6). What if I want to make the door bigger, say with a scale of 14? It only moves down of 6 units, how can i make it go all the way down to its bottom?

EDIT: i found a way to do it. Basically i put the door in an empty father, and i give the dimensions i want to the father, while the door stays with (1, 1, 1). In the animation, i simply move the door from 0 to -1 to open and from -1 to 0 to close

 

Just multiply the movement by the increased scale? Im thinking?...

 

And how can i do that in an animation?

 

You can't.

Just use a script to move the object.