I can see it. If it was one killer then he was a sadist therefore he spent a lot of time fantasizing about different scenarios in which he inflicted pain upon others. It would make sense that he decided to experiment once he made the leap to real life. Only in hindsight do we call this "different MOs." Maybe his MO was simply to torture, abuse and kill women, and his instruments changed to suit his sexual impulses on a given day. Maybe the placement or condition of the victims similarly reflect nothing more than his circumstances and nood. I'm skeptical of behavioral profiling - it's too restrictive and mechanical, at least as it is presented in popular culture. Not every violent criminal follows a script, so to speak. Richard Ramirez really didn't.