Today is likely the day they will post the results of the 1st Quarter NCEPT panel. Last time they posted it on the NATCA website on the first day of the panel at 3pm eastern time. It took another day for it to get posted to KSN, but if they follow the same pattern, it should be on the NATCA website by this afternoon.
As far as what data they go off of, my belief is that they use the last generated priority placement tool, that's why it's listed as part of the NCEPT timeline. I think they just say "estimated" to protect themselves if they end up making changes. We'll see though, my facility had a retirement last week so it should be pretty clear after the selections come out if they're using current data or the last monthly generated PPT data.