BleepingComputer.com: file size between Word 2002 and 2007

I have been working on a word document at home in Word 2002. Sometimes I work on it on campus using one of their laptops which has Word 2007. The file size at home is 1.7 MB (it's 217 pages and their are a couple jpg figures and macros for table of contents, list of figure, and list of tables). When I saved it last on my flash drive in Word 2007, the size was around 1.5 MB. There doesn't seem to be anything missing but instead of copying the flash drive version to my harddrive (and other location), I copied and pasted the changed portions instead just to be safe.

The file is in the .doc format, not docx (although I have the docx converter on my home computer). Does Word 2007 save files differently (more efficiently?) than Word 2002? Is it safe to work between the two versions and copy over the file using "send to" when saving the home version to my flash drive and selecting/copying/pasting (the file icon in the drive's explorer window to the harddrive explorer window) when saving the changes from the flash drive version back to the hard drive? Is there a chance working on the file with different versions of Word might mess it up somehow?

This post has been edited by hamluis: 22 October 2010 - 02:35 PM
Reason for edit: Moved from XP forum to Business Applications ~ Hamluis.