Terrarium Shiny Odds

So I’ve only just started playing the Indigo Disk DLC and i kid you not, i found: a shiny Doduo, Pikipek, Finneon, Comfey, and Espurr all in the 5 ish hours I’ve been playing this DLC as well as a Shiny Duraludon before i even knocked out 40 at an outbreak. Seems like there is no way the shiny odds are the same here lol. I have the shiny charm, but had it quite a while now and i have not found near this sheer volume of random shinies in such a short span. I’ve seen other people question this before, are we ABSOLUTELY SURE the shiny odds are not tweaked within the terrarium?