Silly Bubbles
Necromancer
I'm not sure it is. That is the point I was trying to get over.
ps my keyboard is dieing, lease excuse occasional missig letters
They could make one or more mystery chests per Spire guaranteed and the rest based on RNG. At this moment, the range is between 0 and 48 (4 * 12 chances of getting a mystery chest per Spire). What they can do is to make bosses have a 100% chance of getting a mystery chest. When someone hits an extreme case of 0 or 48 chests, it would take very long time to hit average, making them officially getting different treatment than the majority of the players. When you narrow the range to let's say between 3 and 24, it's more likely that everyone will hit average.
Another solution is to make the same number of mystery chests guaranteed for all player and use the RNG only for the type of prize you get out of them. That's how the game uses RNG most of the time. This makes hitting the average very likely as usually there's not more that 5? different prizes you can get. Not 48 different scenarios that can happen.
PS Please correct me if my numbers are wrong, I haven't 100% checked them.