Yeah, I used the Amazon downloader and I used the key that they gave me on my Amazon "My Games" page. I guess I'll take it up with Amazon.
I wonder if the fact that I still had a Steam version of the game installed at the same time screwed me up. Maybe I should try uninstalling everything and then reinstalling just the CC from Amazon. Does SOTS leave goobers in the registry after it's uninstalled?
EDIT: That was indeed the problem. After uninstalling the Steam version and reinstalling the Amazon version with the key Amazon gave me, the new maps are showing up. I wonder what other goodies await...
So a word of advice to anyone who got frustrated with Steam's anti-SOTS-1.8 policy and bought the Complete Collection elsewhere: UNINSTALL THE STEAM VERSION FIRST. Apparently SOTS doesn't like being installed twice. Even if you bought it four times. (In my case, original game, collector's edition (for the book), ultimate collection, and now complete collection!).
a.k.a. BadKen, badkenbad on YouTube, Steam and LIVE.
Sturgeon's Law: 90% of everything is crud.