It is really odd. I have some old blogs (5y+) which have a decent PR and perform extremely bad, while some newer ones (under 1 year old) that are still N/A and

It is really odd. I have some old blogs (5y+) which have a decent PR and perform extremely bad, while some newer ones (under 1 year old) that are still N/A and perform excellent. Best suggestion is probably as always to not care about PR but just focus on the actual performance.