animation - Flash rotation not consistent across frames -

i noticed seems flaw in flash professional rotation tweens. movie clip rotation tween not rotate consistently frame frame. when rotation slow, seems rotate noticably every 4th or 5th frame, , either not @ or minutely on next 3 or 4 frames. not noticeable unless rotating slowly. 1 might think not worth worrying about, becomes problem when trying subtle animation effects, such cartoon character's slight head movement - looks jittery.

i made flash movie demonstrate problem - here. can done mitigate this?

it rather complicates things, if use object's transformation matrix rotate instead, animation smoother. can guess there sort of optimisation regular animation gets bypassed when you're doing manually.

private var box:sprite = new sprite(); private var boxangle:number = 0; // in radians private var boxposition:point = new point();  private var boxmatrix:matrix = new matrix();  private function updatebox():void {     boxmatrix.identity();     boxmatrix.rotate(boxangle);     boxmatrix.translate(boxposition.x, boxposition.y);     box.transform.matrix = boxmatrix; }