I’m not sure I understand the first paragraph well, but I imagine it like this: when a card is reviewed and it has a new interval ≥ 1000 days, e.g. 1000, or 10000, it is assigned instead a random interval between 1000 and 1200 days.
I am not sure at all how fuzzing is done, but from what I can see in my deck, judging by how there are huge spikes of reviews in certain days in future, there’s no fuzzing applied to the maximum interval whatsoever. Perhaps if the regular fuzzing is applied to the maximum interval, that would do just as well, and perhaps would be covered by the load balancer, too? Or maybe the fuzzing would result in too large of a date range?