There's a number of authentic walk-in cases, where souls have taken over people's bodies in order to carry out important tasks; so I don't see that
this part of Lobsang Rampa's claims is necessarily false.
I've found his esoteric knowledge to be correct. He wrote a lot about 'The Overself' and the incredible powers such beings have, and when I was
reading his books my own overself made its presence known to me; and it demonstrated that it does indeed possess all the powers, and more, that
Lobsang spoke of.
For over a decade I have been interacting with my overself and so I have no doubts that Lobsang was speaking the truth about such beings.