It's usually much less than 6 months. I would say for most of ppl it is around 3-4 months. 6 months is just a conservative estimate in case ppl bother them too much.
For the ppl who got PPR in 30-40 days, it is possible. Like they had their last application rejected due to a minor mistake and they applied it again. Or they were just being really lucky.
I would say, focus on the majority instead of edge cases.
I filtered by Country of residence and then sorted by number of days since AOR. The people in dark green have got PPR and they are all at 30-40 days. Not really edge cases.
Another patch of people at 29-30 days also all in green..
Think some cic officials are really doing their job!