Here is how I've been trying to implement delta time based on different internet resources.

var startTime:Number = getTimer();
game.Update(deltaTime);
deltaTime = Number(getTimer() - startTime) * 0.001;

My issue with this is it doesn't seem to be giving me accurate timing. The main update shows the frame time at 0.001 and when reinitializing the level it goes to 0.002. I'm using dt else where for a timer and later on time based physics so I would like it to work as expected. I must be missing something silly.