Have a look at my script, I fixed that issue.
/t/9226/1
It finds both releases without problem (not that you have a typo in the name of the first artist, it should be "Afghan Whigs, The")
However, this is something which will be changed by discogs very soon. In the future, there will be only one entry in the API-artist-list for releases with different versions.
Read more about that here:
Changes at discogs.com
The changes where anounce for December 15, 2011. But have been delayed to mid January 2012. So there will be an update of my script very soon