I am of the opinion that the pricing for the P1P to P1S upgrade is excessively high, likely intended to dissuade individuals from attempting the upgrade themselves and instead opting for direct purchase of the P1S. This can be observed in the absence of official support for this upgrade in the mentioned post. (source: Firmware upgrade path for P1P to P1S - #8 by tsmith35)
In my view, this practice is rather disheartening, although I remain hopeful that my assumption is incorrect.