My Mfa just shrunk 20 megs??

This has happened one time before, but now i noticed it again when i looked back on my saves. My Mfa file has been around 50-60mb, it was a little above 60megs at most because i keep adding stuff. Now i noticed that my Mfa had shrunk to only 40mb?!. I have not removed anything, more the opposite, i have added a lot of stuff, why have the file lost 20 megs??. I have looked over the game and i cant see that anything is missing eather..

totally confused

It's not a bug, it's a feature! MMF2 keeps sound files in the Data Elements section even after you remove the events for them. When you saved and closed your application, it cleaned this buffer out leaving you with only the sounds you are using :)