I use Scout for analyze application and found out strange thing with ExternalInterface:
I regularly get some overheads with ExternalInterface._evalJS. But I don't any explicit calls of ExternalInterface.call during this overheads. Does it mean that ExternalInterface make internal interactions during flash player lifecycle, or something else?
From the screenshot, it looks like you've registered an anonymous function as the callback for a "timer" event (the "MethodInfo-xxx" is an auto-generated name that Flash gives to anonymous functions), and this function is calling into ExternalInterface. It's your code (or possibly that of a framework you're using) - not internal Flash player functionality.