As i have done a return or two the way it worked for me was if it was unopened 100%. Once i opened it a restocking fee was applied. I think it was 15%. With that said the device still needs to be in like new condition.
Ofcourse that was my experience, and I have had good experiences with them so far.
If you get it just make sure after doing the include you set parm 18 to disable all power reporting. Then connect the devices to the plugs.
