Really? Hmmm. Mine tend to increase in size by 10%~30% (one almost doubled, and it was several MB to begin with), depending on I haven't the slightest idea what.
Maybe it's the version of Word? That doesn't really make sense though....
Anyway, if I can figure out how to make BookDesigner accept my font and font size choices (I haven't played with it much yet, but it seems pretty determined to only output its defaults), I think I'm fairly likely to start putting my files into LRF for reading on the Reader. Then it wouldn't matter much, 'cause I'd just zip up the originals and go on with my life.