v9 to v8 - Miracle, or just lucky?

I know there's no built-in way to save a v9 file back to v8 format. But, being curious (and procrastinating starting a new project) I tried something, and it worked - at least in my 2 trials. Knowing that the cptx files are just zip formatted files (like pptx, etc.) here's what I tried:

1. Change the extension of the v9 file from cptx to zip
2. Unzip the files
3. Open the info.cpi file in a text editor (like Notepad)
4. In the first line, change the version number from 9.0.0.223 to 8.0.1.242
5. Save the file
6. Re-zip all the files
7. Change the extension of the new zipped file from zip to cptx
8. Open the new cptx file in v8

I tried this with both a very simple file started in v9, as well as a complex file (video, actions, quiz, etc.) that was started in v8, but finished in v9. (I did notice that the version number in the info.cpi file of the simple v9 file was listed only as 9.0..223 [missing a 0] but changing it to the full v8 number still worked.) The complex one even had knowledge check questions - they got converted to normal quiz questions. So far, I haven't found anything else in that file that didn't convert properly.

I'd be curious if someone could replicate this. I also haven't tried a responsive project.