Thank you all for your concern and responses.
I must take issue with AUDYAPLAYER, since I don't want people posting false solutions:
There are 2 ways to edit a style on a Tyros. The first is to do a global edit. You change the mixer settings outside of the Style Creator, open the Style Creator, and simply save. This saves those mixer settings for every part and variation.
The second way is to do a specific edit on a specific part. To do that, you need to be IN the Style Editor.
This is the way it worked on the Tyros 3, 2 and 1.
In both cases, you NEVER have to press "Execute".
If you had paid more attention to the first half of my video, you would have seen that the first time it worked.