Alpha fade in almost working, but not quite

I am trying to do an alpha fade (in) on a movie clip container that contains a jpeg. It seems to be working somewhat, but does not fully fade in (when set at a lower number) or just jumps to be 100% alpha, (when set at a higher number) I am using a small delay on the loadMovie command as well and I am wondering if this is what could be causing the issues since the alpha fade code works fine on its own.

holder2._x = 550;
holder2._y = 112;
function loadIn(movie) {
loadInterval = setInterval(loadIn, 1500, "intro1.jpg");
_root.holder2._alpha = 0;
_root.holder2.onEnterFrame = function ()
		if (this._alpha < 100)
			this._alpha += 2;
			delete this.onEnterFrame;

I have tried adding this in as well, but it did not make a difference:
if (_root.holder2.getBytesLoaded() >= _root.holder2.getBytesTotal() )