Make a change every 0.02 seconds precise

I want to make something to change it’s position every 0.020 seconds and after it finishes one cycle, speed it up to 0.019 and so on. I tried working with decimal but still not precise enough. Please help ^^

I do think its not possible but i suggest you looking at how Time.deltaTime increase by time. Create a variable and set it to something like;

private var a : float = 0;

function Update()
    a += Time.deltaTime;

See how a value increases per frame, then you might have to see the chance whether it is possible to detect that small amount of change in seconds.