I own a Prime 4 (same software) and just invested in a Numark Mixstream Pro Go. It’s a great unit but lacks one thing that makes it usable for many DJs. I’d hate to send it back if the crossfader reverse function is not made available. The only way I can use the Numark reversing the crossfader is using Serato, which defeats the purpose of even buying a standalone unit. I’ve been DJing since 12years old this way and would love to have the ability to use this unit, but it will have to go back if this isn’t possible like the Prime 4.
Even if they were looking at changing it, they won’t be doing it next week so you’re going to have to make that decision. Either send it back or expect to wait several months at a minimum for it maybe being added.