ActionScript 2.0 :: Make The Rollout Animation Shorter?

I am working on a flash site where I want the buttons to animate on Rollover and reverse animation on Rollout. Here is the code I am using at the moment.

onClipEvent (enterFrame) {
if (this.hitTest(_root._xmouse, _root._ymouse, true)) {
this.nextFrame();
} else {
this.prevFrame();
}

This works fine but I would like to go one further. Is there a way for me to make the Rollout animation shorter?

So if the button animation is 60 frames long can the Rollout animation occur from say frame 30 on Rollout? The play head needs to jump to frame 30 on Rollout and I have no idea how.

Of course if the playhead is only on frame 20 then on Rollout the animation will reverse from frame 20. (not from frame 30).

This way the Rollover animation will be the focus and the Rollout is...well simply a Rollout animation. Short and sharp.