The ‘uwt’ parameter is included intentionally — some users use external script to change this bit so wanted a way to directly modify it without having to pass in the entire program parameters. So ‘uwt’ and ‘en’ are provided to directly change these bits without having to pass in the rest of the program data.
You are right that if either of these parameters are present, the rest of the program data is ignored. I will clarify it in the document.