I think we'll still want '19' right @ Morganza Road due to the ramps to NB I-79 still getting the #18B number (and can be considered as 1PPI with the other ramps for I-79), while Morganza gets #19.
Also, don't know what they are thinking making that a left-on merge from I-79 NB to PA-576 WB when they extend the highway in the future. Maybe it will have a divider in the future to prevent idiots from dive-bombing the #18B ramp to I-79 NB in case there's a backup on I-79 itself and they want to try to bypass it.