Since Delves came out. I (and many others) assumed that the multipliers for treasure are dictated by room Rarity. They aren’t… Like at all. Even the same exact rarity for a room on the same delve will have different treasure multipliers.
Ahhh so the multiplier is fixed to the room you get on the delve. They never change. Thanks.
So basically it really only effects Delves like Crypt Keepers where the bottom room can be varied from 2-5 for Rarity.
Some rooms within a rarity have a better chest upgrade chance and some have a better multiplier so I expect the combination of the two rewards has been “balanced” for each rarity.
Room rarity just dictates troop level (e.g. troops in a rare room are 60% of delve level). The multiplier feels like it is tied to perceived room difficulty, rooms with nasty troops (e.g. transformers, insta-killers) or nasty post effects (e.g. tidal) tend to have higher multipliers.
Every level of room falls in a range of difficulties and range of rewards. There is some overlap. So some level V rooms are easier and give less rewards than some level IV rooms.
Overall it means if you do 3 level V rooms and compare them to 3 level IV rooms, you might end up getting more from the level IV rooms. But if you do 50 of each, you’ll find the total rewards from the level V room are at least slightly better.
So it’s true that if one Faction map has more higher-level rooms than another, it will on average give better rewards. But it’s also true you might try an individual run and get dramatically fewer rewards than you did on a run of a Faction map with lower overall levels.
For some reason, human psychology finds this more exciting than a more predictable rewards curve.
