In a different thread two people wanted to "correct" a calculation of awarded xp of mine, by pointing out the xp multiplier from the table in the DMG on page 82. Then others chimed in, pointing out that those multipliers were only for calculating encounter difficulty, not for awarding xp. That evoked two questions in me:
- How many people are using that multiplier for awarded xp?
- And wouldn't that actually be the better way?
If we say that 6 goblins in a pack are twice as difficult than 6 single goblins in a row, wouldn't it be only logical to give more xp for the harder encounter?
When 5E first came out, I experimented with giving out multiplied XP for XP awards. It didn't last long for two reasons:
(1) It was waaaaay too much XP. I can handle giving 3rd level PCs 5,000 XP each for winning an insanely difficult fight, but 20,000 XP just seems wrong. It wasn't THAT hard.
(2) It makes it way too important whether the DM chooses to count a string of related interactions as a single encounter with multiple foes, scattered over an area; or a series of separate encounters. Normally it doesn't matter what the DM
calls a given encounter as long as it behaves correctly, but this rule had the potential to give players reason to intrude into an area of the DM's responsibility: adventure construction. ("Was that one encounter we just had or five? Did we get the full x4 XP award for everything?")
I didn't think of it at the time, but there is also:
(3) You'd still have to come up with rules for how to treat circumstantial adjustments to difficulty which don't get reflected in the XP budget. The DMG says that if the PCs are all surprised, for instance, you should mentally bump up the difficulty by one level--but that doesn't technically multiply XP any, so you'd still have to wing it if you wanted to grant extra XP for extra difficulty.
Finally, the XP multiplier is just a crude rule of thumb anyway. It exists to roughly replicate Lanchester's Square Law of battle. If you
really were trying to scale up XP earned based on difficulty you'd probably be better off just eyeballing things. A 3rd level Aarakocra vs. an Iron Golem on a mountaintop isn't a difficult encounter at all, no matter what the XP budget says. Adjusting XP by "difficulty" is a thorny problem indeed, one you'd basically need to start from scratch. CR vs. PC levels won't really help you.