My Transcoder default buffer is set to 600 seconds / 10 minutes, but Plex only ever buffers 60 seconds beyond my current place in videos. This is even if I wait for a long time with the video paused so that the buffer can catch up.
I’m usually just using the web player @ app.plex.tv, rather than PMP or the new app.
That’s not what that setting does. That setting sets the buffer on the server side of how much transcoded data PMS produces ahead of time for the client to be able to request. It does not affect the buffer on the client end.