Here are two interesting things if anyone has any ideas...
I decided to try Flash Builder 4.7 (although still staying with 4.6 for main work).
I installed Flash Builder 4.7 on a new fresh windows 8 machine. I migrated one of my projects over. I then installed the 4.8 sdk (using the automated apache install), then I compiled my project and the file size went from 774k to 1770. No changes made to the code. I find it hard to believe that the sdk got worse? Going back to the old sdk results in a smaller file again... but...
...another weird behavior. So i switched it back to sdk 4.6, and recompile- the result is the right size, however only a few seconds after compilation has completed the file doubles in size to 1500k, which just so happens to be the debug version size... this new double sized version has replaced the good export. However if I am quick I can copy the export build out before it gest overwritten by the bad debug build. Any thoughts? The only thing that is different is this is windows 8? Shouldn't matter though right?
The automatic build was set which was running shortly after an export and this was the problem. The sdk compile size I still have no idea on but that is not a big deal- I can just stay with 4.6.