PW hosts the MP3 files, and apparently their recital site is programmed in such a way that the recital order is based on the order in which the music is uploaded. And if someone uploads a new version to replace the old one, it resets to the bottom.
But here in PT we all host our own files, so the order in which we submit the post is leading. Technically we could "cheat" and submit something without any music, and then add the link to the video later by editing the post. No idea what purpose that would serve, but... it's possible π