What version of Pokemon Blue you're playing? (VC? Emu?)
I ran around with 30 Max repels and a Lv 12 Pikachu as lead, at the claimed Route 4, and no Lv 12 Raticate appeared.
As of present, unless better proof is presented, I'm inclined to believe the datamined resources.
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edit: @Kaphotics Assuming that there isn't a glitch in the game, with how it pulls the levels from the encounter table,
I postulate that the Lv 25 Crabrawler is a programmed encounter.
Interacting with that particular tree's berry pile for the first time will activate the encounter (my every first encounter so far, has been lv 25).
(additionally, I'll like to note that SciresM's shiny patch code is active, and the Crabrawler isn't shiny. Meaning this encounter is shiny-locked
I made a mistake and the code wasn't on. This encounter can be shiny.)
[If you run away from the Crabrawler, the fixed encounter will happen when you try to interact with the berries again]
(my tweet showing the image, when I did the testing) (second tweet, with shiny code properly working)
Anyone with the know-how can dig through the list of fixed encounters, and it'll be there