No, I was needing to know if the users would get the edited version if I didn't re-upload the file to the super container. The whole point of this system is that it needs to be completely computer automated after the IWP user presses the 'Convert to PDF' button.
I realised, however, that I had over-complicated the system. I can use a normal filemaker container field and reference the file as long as it's stored in the web folder in FileMaker's program files. FileMaker automatically saves over that PDF file when the user hits the 'covert to PDF button' and, as only a reference to the file is stored, the user gets the latest version of the PDF when they download it.
We will still likely buy super container for our IWP uploading needs however, thanks for your assistance.