In the future please made pre-order codes also work as registration code?

[Doki]

Can you pretty please make a singular code that acts as both the pre-order code AND the registration code for the next expansion? The current method causes a great deal of confusion, and extra frustration/panic when shipping issues occur.

[Nekodar]

I believe the reason for two codes is that its for different entitlements...
Registration code just entitles you to play the expansion content. (Possibly CE items for CE reg code)
The preorder code is what give you the preorder items and the early access entitlement.

Sure it could be done better ways, but it's probably done this way because it's easy to separate what the code entitles you to get.