I'm willing to bet that if I did a UOA at 6 months with a sample of my oil, and kept running the same oil for 6 more months and did another UOA then, that both UOAs would show that I still had plenty of life left in my oil.
What I'm saying is that I might possibly run my current fill until May 2023, and maybe do a UOA then to see how the PP held up for 12 months at about 3500-4000 miles.