Yes. Since you listed this in credits, my XNK should convert to credits on your end. You can then convert your credits to XNK when you want to. 1 XNK = 3850 credits. My 80 XNK equal 308,000 credits. Feel free to change it to that if you want instead of 300,000; I just threw 300K out there since it's a round number.
As far as I know, you cannot convert back to credits. You can keep your existing credits until you decide to convert over, but once you convert to XNK, you're stuck with XNK. It shouldn't matter in a week or two once all of the old credit listings expire anyway.