easing movement

I've been trying to implement my own tweening/easing movements based off robert penners equations.

I've started with the simplest linear movement and got it working but the movement time doesn't work how i expect. I'm not sure if it's my code which is wrong, how i've implemented the formula, or my understanding of constructs ticks and time.

I've set the duration to 1000 milliseconds which is 1 second. The function is updated every 0.001 second which adds 1 to the objects elapsed time, 0 being the beginning and 1000 (duration) being the end, so 500 would be the half way point.

Could someone please take a look and see where i'm going wrong.

Much appreciated.

construct file

I recall there's already a easing behavior called EaseTween. It's also based off robert penners equations. Check it out: scirra.com/forum/behavior-easetween_topic53288.html

you can always use lerp

... Easing in the movement of an object

lerp(Object.X,Desired.X,dt(multiplied)10)

will make an object X smoothly ease toward the desired X

Thanks for your replies guys, i know about the behaviour but wanted to have ago coding it myself. It might be my MMF background making me wary of using 3rd party stuff as developers disappear and things never get updated.