Extra iteration in mx.effects::Effect/stop()

Reviewing source for mx.effects::Effect/stop() in SDK 3.4.1.10084, lines 956-965:

public function stop():void
{
var n:int = _instances.length;
for (var i:int = n; i >= 0; i--)

{ var instance:IEffectInstance = IEffectInstance(_instances[i]); if (instance) instance.stop(); }

}

Isn't this doing an extra iteration in the beginning, due to "var n:int = _instances.length"?