We worked our way through The Three Keys - the First Key. We got used to the patterns of kill 10 x mob_X, read the book, kill another 10 x mob_X etc kiliing 30 of each mob until you got to the end. Now this is pretty mind-numbing and unimaginative but we were in the zone anyway and it kept us occupied.
We moved on to "The Three Keys - the Second Key". The mobs were a bit harder and a bit harder to find. Some were yellow to us.
One could be forgiven for expecting "The Three Keys - the Third Key." would be a progression on from this but no. We are now back to grey mobs - some of the lowest in the zone in fact. We killed 30 and the next 30 are also grey.
I suppose the moral is:-