its been a while since I've worked with the dreaded 'preloader' and have a few questions ...

if i am calling audio files using unique identifiers (so no physical instances on the timeline) will the file weights of the audio be accounted for in the preloader, or will it only reflect content that is actually sitting on the timeline?

if they're brought into the Library and exported as linked items, then your calculations of bytesLoaded versus totalBytes will be accurate....

but if you're calling them externally from a folder beside the .swf then NO.

I strongly recommend with the dreaded preloader, to make sure the instances in the library are not set to "export on first frame", as they will then be loaded before any preloader code can kick in.

Better to have a 3 frame movie- frame 1 has preloader code, with a gotoAndStop(3) when the movie is loaded. Frame 2 has instances of the linked items on the stage - which will never be seen/played but will thus be included in the preload, frame 3 has the actual website.