I'm having a hard time understanding how the PC can "only affect the OAV".
The problem to me is that OAV is a measure of events, not an event itself. I don't see how a rating can effect a measure directly. It seems to me that ratings would determine events only. It's not like hitters' splits affect batting average. They affect whether events become hits or outs (along with a whole bunch of other things obviously). The batting average is a measure of the effect, not the effect itself.
If PC rating determines something, it must, by definition impact some part of the formula that determines events. It cannot just "affect the OAV". This makes zero sense.