With Premiere, you are not editing source files, but with Audition, you can, and sounds like you are. Audition also has it’s own project file, .sesx files into which you import audio source files. If using this type of editing method, your original source material will not be overwritten, just like in Premiere.
The Auto Save backups are of the .sesx project file, not the original source files, however when you save a .sesx project file the first time, Audition asks if you want all source files to be copied to the folder containing the project file, if they aren’t already there. At that point Audition will have given you ample opportunity to have duplicate source files.
If you are editing source files, those source files ARE your ‘project files’, and the only way that Audition can save any edits is to overwrite that file at each save.
Steve Brame
creative illusions Productions