Imagine finding a random number between 0 and 100 in a random calc and saying this is now a percentage guys. Politicians always lie is a universal truth, even MMO mayors feel the need smh
Also tbh the suggestion would be healthy if the rate is under 1/10k (doesn't have to be rarer than shiny otherwise it will generate frustration for shiny egg hunters that will find it but not the shiny they were looking for). About the maths, since you need at most 32 breeds for a 5x31 natured, the probability of it happening during the process would be 0.003195, so about 0.3% and obviously most of it would be just breeders being duplicated, not finished comps ^^
Otherwise the question is do we really NEED this ? Like most of the suggestions which are made on this forum, the answer is no and so it will most likely never be implemented