Hi - thanks for your feedback!
Our for 24fps just checks the framerate of the file. We don't change the frame rate. Your 18fps file should be playing at 18 fps.
We currently define "animation time" by listening to screen updates that the player does. It might be the case that your SWF does stop playing, but some libraries, undeleted timers, etc. still force the player to update the screen. Perhaps you have some ongoing animation via actionscript, thus failing the spec.
Could you please review your file and let us know if there are animation timers or libraries involved?
Yes, we rely heavily on things like TweenNano and our own custom coded animations.
I was thinking about ways you could test it. Lets say, at the desired time, you could capture bitmapData of what should be the final frame, then capture several other frames afterwards and compare the bitmapData. That way you can difinitively tell whether or not the swf had stopped visually playing back.