The short answer is that no, it would not work on a bounce back. If you get a bounceback rate from Disney, general speaking, it most likely won't be beat by any Orbitz discount. I'm sure people will have examples to the contrary.
I've booked through Orbitz once, so I am answering from my recent experience and how it worked for me.
I was looking for a discounted room for Grand Floridian for February of 2016. I wanted a outer building garden view. Disney released their general public discounts and the discount through the Disney website was 15% off for the category that I wanted. That did not make me happy. Soon after the Disney general public release of discounts, I went to Orbitz and they were offering the same room category at the same discount of 15%. I have no idea if Orbitz buys blocks of room from Disney or not, but I digress. At the time, Orbitz then offered an additional 15% off. For that particular Orbitz promotion code, the 15% was limited to a total of $150.00, but I figured saving another $150.00 off our trip was better than the price Disney was offering, so I booked through Orbitz. No problem, I got my confirmation number and linked our reservation to
MDE. Several days later, Orbitz then offered their 48HRSALE. The same category that I wanted was still being offered at 15% off through Orbitz. The 48HRSALE code and that Orbitz was offering allowed me to book the same category of room, but instead of $150.00 cap, Orbitz was offering a true additional
15% off of the price that Disney was offering. So I made a new reservation through Orbitz and cancelled my previous reservation,
thus giving me a 30% discount, instead of the 15% that was being offered if I booked directly through Disney.
Please note, Orbitz does not offer all room categories at a discounted price all the time. As I said, it seemed to correspond with the release of the Disney general public discount and Orbitz had the room category that I wanted at a discount. Also with Orbitz, you have to pay for the entire stay at the time off booking.
Hope this makes sense.