Meh, I respect the work you put into it. I'm not arguing any numbers or formulas you are using.
But just by the eye test and history I put Dan Henderson higher and Rampage lower. Also not sure why Ken Shamrock makes it but Royce doesn't?
Actually I do have Royce on the list, just is a little bit lower:
33. Ken Shamrock - ( 682 )
34. Cain Velasquez - ( 679 )
35. Benson Henderson - ( 678 )
36. Renato Sobral - ( 674 )
37. Hayato Sakurai - ( 668 )
38. Jake Shields - ( 667 )
39. Vitor Belfort - ( 657 )
40. Paulo Filho - ( 655 )
41. Royce Gracie - ( 652 )
Now, you can argue that Royce should be higher.
I say, he was dominant in 1994, but most of the fighters in those first few UFC tournaments had no name and no skills.
Ken had much better competition in Pancrase and later in UFC.
But it is close - 30 points difference.
This career graph might help here:
Ken had higher peaks and a longer career, but overall their historical career line looks similar.