ActionScript 3.0 :: FadeIn + Fadeout Multiple Movieclips With One Button?

I'd like to build a fairly simple website where the pages fade between each other, after looking around and remembering what I could from having Flash MX (can't remember which release) all those years ago I figured the best way would be something like this:

Pages as movieclips, these would be placed inside the stage, i.e. with space around them, and buttons along on side which, when clicked will fade in one 'page', and fade out any others where the alpha is at 1.

That way, using only one frame in the main timeline and not having to create fading tweens in each movieclip I can navigate freely between the pages in any order.

I managed to get to the point where I have two buttons and to movieclips, when the first button is pressed a 'page' fades in, and when the next is pressed the first 'page' fades out as the second fades in. However the fade out is delayed and much slower than the fade in, rather than faster as it should be.

Here's the AS
page2btn.addEventListener(MouseEvent.CLICK, fl_MouseClickHandler_4);
function fl_MouseClickHandler_4(event:MouseEvent):void
{

[code]....

how I might restructure this to get a the visual results I want in the most efficient manner?