I truly don't know if I could consider AmericanMom's application as a Non-Priority. 34 days is extremely quick (15 Business Days shorter than the quickest NP) especially considering the trend of the other NP applicants.
I would think it's more likely that her retroactive upgrade was honoured. If you consider her as a NP, that seems to skew the NP average. Like if we considered marenleigh's wait as indicative of the "average" even though her visa application had been lost and found afterwards.
Edit: I understand including her for transparency's sake, but I think it unlikely that she was NP as her wait is closer to a Priority applicants wait than the NP.