It was just something I had read on a site. The first pos opk is what I've always heard & I guess it is, because I ended up calling Clearblue Easy & they said you should go by the first one, but if that's the case I think ovulated a day or two before FF is saying I did. I don't even care at this point, I'm just so happy I got cross hairs this month!
ETA: Oops! After I posted this, I realized FF changed my O day to the day before the original day they had given me, so it def makes sense to me now that it would be the 1st pos.