The backup file is a single file (about 21megs in size) not a compilation of posts that I can GRAB older posts from - it is NOT like a file cabinette where you can pull stuff from, more like one big locked box.
I save 2 versions of the backup - backup 1 on dates ending in odd numbers, backup 2 on dates ending with even numbers - if I were to reinstall and older version, it automatically wipes out all newer posts and if I reinstall the latest version, it over-writes the older file, losing previous data that was saved.
Both options are actually ugly - in that, installing the oldest will erase all newer members and posts and previous layouts - installing the newest can often lose posts that were present in the older backup.
So, I once something is deleted, and it says "you sure" that's it, it is gone. The only way to save every blunder (however they happen) is to have a hundred backups, which isn't feasable.
Hope that helps. I hate seeing stuff get lost too, but it's the nature of the beast. Hopefully, we'll see less problems with the version update now in place. I'm still running around fixing the logos in all the forums - there are a bunch of them.