Yes. It has worked with getting Fast Passes at other parks as well. If any other DIS'ers want to give it a go and get back with this thread, that would be cool.
The last time we did this was two weeks ago. We were at Magic and did our three original Fast Passes. Set down to eat, tried to book for Fast Passes at the Studios and it said we had "conflicts". It gives you prompts to replace your old (already used) Fast Passes with the new ones you just booked. We did it and had no issues.
Next time I do this I will grab some screen shots and post them on this thread or maybe start a new one just for that purpose. Heading to the parks early on Saturday so I can get home to watch The Derby or on Sunday, not sure which yet. I will try and do it then if I can.[/QUOTing