Well no. The distance between the previous number and the next one determines the rarity. Unless I’m wrong, “rolling” is less than or equal to 75 means that if the numbers 2-75 are rolled in the numbers 1-10000, then Gleam would be rolled. The RNG system works, but having less auras and larger numbers means that there’s more of a “truly randomized” feeling.
I mostly pulled the RNG system from this guide, but it no longer has any images: