Yeah I think I'm also aware of it...I mean, the PID is not that consistent :/
Just 2 hours ago, I finally caught a Timid Female 31/27/31/30/31/31 Volcarona, HP Electric...but not without getting a lot of spitbacks (Relaxed, Docile, non-Timid nor non-Modest natures).
I think the PID depends on the target time or something...that's why I changed my target time to catch that Volcarona.
BTW I have to post that recent catch of mine, but I don't like to be in the last post...people will ignore it :/