kbnrylaec: REMOVE Neverwinter Nights (was 17%)
It doesn't show up in nav bar search results, or on the little game tile on store pages, but the discount still appears on the game's product page, in the cart, and at checkout, as long as you already have
Neverwinter Nights Diamond in your library.
I doubt the discount works with
NwNEE itself, so if you didn't already own the old Diamond edition, putting the Beamdog version and
NwN2 in your cart at the same time would probably not give any discount for either.
Edit before posting: I checked quickly in a private window session (not signed in, so it wouldn't detect that I own
NwND), and indeed, there doesn't seem to be any series discount between Beamdog's
Neverwinter Nights: Enhanced Edition and Hasbro's
Neverwinter Nights 2 Complete.
This means it's also a one-way deal: you can get the 1/6 discount on
NwN2 by already owning
NwND (either from when it was sold on its own, or from buying the EE and getting it auto-added to your library); but owning
NwN2 won't give you a discount on
NwNEE, since the old DE isn't in the cart, it's just added to your library later. (There's also no permanent discount on the enhanced edition for owning the old Diamond edition.)