i've traded in FIFA 15 ultimate that has the special code used and amazon gives me full value even though those codes were redeemed (there's probably no way for them to tell unless they attempt to redeem the codes), here the FIFA 15 ultimate has a different upc than FIFA 15 regular.
however in this case, most people who wants to dump the kinect that came with the console will probably be SOL not because of your dance central voucher, but the fact that they probably want the standalone x1 kinect retail box that has its own unique UPC in order for you to get $110 out of it.
as for amazon, I've dealt with them before on a XBOX 360 trade in a few years ago. the company that took the machine returned it, but the box was damaged when they returned it, either it was damaged in transit to the trade in company or they decided that it wasn't up to par and damanged in transit back to me. I bitched about that to amazon and they gave me the credits that they promised back, but YMMV.