New
#11
Yep, that's a normal retail key for a Windows 10 Pro. The only thing I can think of is that it may be a special key only for a BizSpark version, and could be why it's not upgrading with it.
I'd keep trying to see if it may let you. If not, then I'd contact Microsoft to see what they say for why it can't upgrade. It'll be interesting to hear what they say.