The .sav were probably made when you used SC4Tool to change properties, they are backups, and should not be in plugins (you can turn backups off in SC4tool). In this case, I guess you changed the previewable to true, so your bakckup had it as false. When you datpacked everything, the .savs superseded your .descs (because "s" comes after "d" in the alphabet), and you were back to your original files.