How do honey trees interact with the trainer ID changes?

Question

For context in Generation VII the trainer I'd was changed to a 32-bit number, with the first 4 digits acting as the secret ID and the last 6 digits acting as the trainer ID.

Back when honey trees first existed the trainer ID and secret ID were both 16-bit numbers, allowing easy calculations of where the Munchlax trees were.

How do the honey trees calculate what ones are Munchlax trees given the ID change? I ask because I have a few challenge runs where I will need Heracross and would like to maximize the chance I get it.

Comments

Try this (enter Trainer ID and it'll tell you which trees have Munchlax):
https://www.dragonflycave.com/sinnoh/honey-trees

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Are you asking for a mathematical explanation behind it, or do you just want to know which trees will give you Munchlax? If only the latter, this might help: https://lincoln-lm.github.io/JS-Finder/Tools/BDSPMunchlax.html