ActionScript 3.0 :: Smoothly Rotating Object Towards Mouse

I am trying to make an object smoothly rotate towards the mouse.
ActionScript Code:
var rot:Number = 0;
var smoothing:int = 5;
stage.addEventListener("enterFrame", step);
function step(e:Event):void {
// point_direction is a function I have created that finds the angle between 2 points. I know this functions works as it is supposed to
rot = point_direction(obj.x, obj.y, mouseX, mouseY);
obj.rotation += (rot - obj.rotation) / smoothing;
}
This code works, except when I pass the mouse over the center of the object on the left side it seems to spin the long way around. So if I move the mouse down the center of the object on it's left side, it will spin a long way counter-clockwise to reach the mouse instead of the tiny length if it had spun clockwise.