The pair specific categories were not removed, they were made sub categories of the pair types they belonged IN. It helps to make it so that the query load is less, which is better for the database.
move from het>Anita/Richard to Threesomes
http://books.adult-fanfiction.org/story.php?no=600000450
http://books.adult-fanfiction.org/story.php?no=600093373
http://books.adult-fanfiction.org/story.php?no=600093356
move from het>Anita/Micah to Threesomes
http://books.adult-fanfiction.org/story.php?no=600005476
move from het>Anita/Jason to Crossovers
http://books.adult-fanfiction.org/story.php?no=26962
move from het>Anita/Edward to Threesomes
http://books.adult-fanfiction.org/story.php?no=600005780
move from het to het>Anita/Jason
http://books.adult-fanfiction.org/story.php?no=2941
to be moved to Anita Blake>Het
http://books.adult-fanfiction.org/story.php?no=544214624
to be moved to Anita Blake>Threesomes
http://books.adult-fanfiction.org/story.php?no=600093348