That 39.4 looks like a winner. 39.2 was my original prediction.
Side note: I have been scouring the interwebs on any forum I can find for OCW's and ladder tests. I have found several dozen, going all the way back to 2005 I think was the oldest one I found.
From those I've found where a definite winner emerged, I would say that out of every 10 of them, 9 ended up being at 2% off of max or 2% + 0.2 grains from max. This includes all calibers from 338 wildcats to 223 Rem.
I am not willing to say it is definitive, but I can say that it pops up so often that it shouldn't be ignored. Just a trend I've noticed. Do with it what you will.