[FX2004] Scrolling Movieclip

I have a movieclip(artThing) on my bottom layer, with a mask on the next layer(masking the movieclip). And on the top layer the scroll buttons.

The scroll buttons increment the Y inside a “if” statement so it stops scrolling after a certain #

Problem is, it isnt stopping and it just keeps scrolling. The following actionscript is for the Up Button.

onClipEvent (enterFrame){
        if (textScroll){
			musoY = _parent.artThing._y;
			endNum = -416;
			if(musoY == endNum) {
				textScroll = false;
			} else {
                _parent.artThing._y -= 16; // or +=1;

It scrolls fine, but it keeps going and going.