Videos double (or more) in size AFTER editing in Movie Maker (Windows 7)

I have tried every setting available and even tried creating my own, but every time I edit a video and try to save it, it doubles (at the very least) in size.  I have adjusted the preferences to match the video size and bps etc etc. as well as the audio when I'm saving it, but a 125mg video will save at well over 250, often a lot more.  Why, especially when I have edited segments OUT of it?  I want to burn a DVD from  the videos I'm working on. I've tried that setting, as well as (as I said), using custom settings.  I've tried save for computer, DVD and every single other one on the list, but they ALL wind up creating double sized files instead of compressing them.  Heck, I'd be happy if they saved exactly the same, except for the editing out, which should lower the file size in and of itself.