I've never heard of the former term. The latter term "multiple personality" is now known as Disassociative Identity Disorder, which conceptually is about the same (clinically, not according to the movies and whatnot).
Seriously though, I have no idea what multiple angle of personality is. Its not in any textbook that I have seen and even google doesn't pick anything up.
If I were guessing I'd say it was someone with a poor grasp of English grammar trying to say that an individual may only have one personality, but that personality will be viewed in different ways by different individuals.
Total guess though, and its definitely not a disorder.
