No. The number generation is random so let's use 10! For example (that is 10x9x8x7x6x5x4x3x2x1) so that is the random number generated for the Thagomizers. So to every Ultra in the game let's say there is a 2! Is assigned to all those Ultras EXCEPT Valus Ta'urn. His is let's say 8! So 10!/8! There is a higher chance it will drop for him as opposed to it dropping at 10!/2! So you're chance at getting said exotic would be 1 in 10!/2! Which is (10x9x8x7x6x5x4x3)Because that's the value set for the Thagomizers. But if you do Valus. And it is 10!/8! Then it is only (10x9). Now I'm no expert in RNG or computer science and coding but that's how permutations and probability work, I could be way off. I'm just using my knowledge to the best of my ability to help you understand